diff --git a/Cargo.lock b/Cargo.lock
index b498793..6b2da36 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1046,6 +1046,7 @@ dependencies = [
  "glob",
  "hostname",
  "indicatif",
+ "minijinja",
  "os_info",
  "regex-lite",
  "serde",
@@ -1055,6 +1056,7 @@ dependencies = [
  "thiserror 2.0.18",
  "toml 0.8.23",
  "walkdir",
+ "which",
 ]
 
 [[package]]
@@ -1106,6 +1108,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "env_home"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7f84e12ccf0a7ddc17a6c41c93326024c42920d7ee630d04950e6926645c0fe"
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -2030,6 +2038,15 @@ dependencies = [
  "unicase",
 ]
 
+[[package]]
+name = "minijinja"
+version = "2.15.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b479616bb6f0779fb0f3964246beda02d4b01144e1b0d5519616e012ccc2a245"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "minimal-lexical"
 version = "0.2.1"
@@ -3716,6 +3733,18 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "which"
+version = "7.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d643ce3fd3e5b54854602a080f34fb10ab75e0b813ee32d00ca2b44fa74762"
+dependencies = [
+ "either",
+ "env_home",
+ "rustix 1.1.3",
+ "winsafe",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
@@ -3918,6 +3947,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "winsafe"
+version = "0.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d135d17ab770252ad95e9a872d365cf3090e3be864a34ab46f48555993efc904"
+
 [[package]]
 name = "wit-bindgen"
 version = "0.51.0"
diff --git a/crates/doot-cli/src/commands/apply.rs b/crates/doot-cli/src/commands/apply.rs
index 877e0b7..6746c8d 100644
--- a/crates/doot-cli/src/commands/apply.rs
+++ b/crates/doot-cli/src/commands/apply.rs
@@ -3,7 +3,7 @@ use doot_core::state::{StateStore, SyncStatus};
 use doot_core::{Config, Deployer};
 use doot_lang::ast::HookStage;
 use doot_lang::evaluator::{DotfileConfig, HookConfig};
-use doot_lang::{validate_dotfile_targets, DotfileConflict, Evaluator};
+use doot_lang::{DotfileConflict, Evaluator, validate_dotfile_targets};
 use indicatif::{ProgressBar, ProgressStyle};
 use std::io::{self, Write};
 use std::path::PathBuf;
@@ -112,7 +112,11 @@ pub fn run(
 
     for dotfile in &ordered_dotfiles {
         let full_source = source_dir.join(&dotfile.source);
-        let status = state.check_sync_status(&full_source, &dotfile.target);
+        let status = state.check_sync_status_with_template(
+            &full_source,
+            &dotfile.target,
+            Some(dotfile.template),
+        );
 
         // For directories, check individual files for smarter merging
         if full_source.is_dir() {
@@ -124,7 +128,9 @@ pub fn run(
             for (src, tgt, file_status) in changed_files {
                 match file_status {
                     SyncStatus::Synced => {}
-                    SyncStatus::NotDeployed | SyncStatus::TargetMissing | SyncStatus::SourceChanged => {
+                    SyncStatus::NotDeployed
+                    | SyncStatus::TargetMissing
+                    | SyncStatus::SourceChanged => {
                         // Can auto-merge: just copy from source
                         has_changes = true;
                         if verbose {
@@ -185,10 +191,7 @@ pub fn run(
                     conflicts.push((dotfile, status));
                 }
                 SyncStatus::SourceMissing => {
-                    eprintln!(
-                        "  [error] source missing: {}",
-                        dotfile.source.display()
-                    );
+                    eprintln!("  [error] source missing: {}", dotfile.source.display());
                 }
             }
         }
@@ -255,7 +258,9 @@ pub fn run(
                         dotfile.source.display(),
                         dotfile.target.display()
                     );
-                    println!("  [s] Use source  [t] Keep target  [d] Show diff  [m] Merge in editor");
+                    println!(
+                        "  [s] Use source  [t] Keep target  [d] Show diff  [m] Merge in editor"
+                    );
                     print!("  Choice [s/t/d/m]: ");
                     io::stdout().flush()?;
 
@@ -307,7 +312,11 @@ pub fn run(
         } else {
             println!("\n[dry-run] would deploy:");
             for dotfile in &to_deploy {
-                println!("  {} -> {}", dotfile.source.display(), dotfile.target.display());
+                println!(
+                    "  {} -> {}",
+                    dotfile.source.display(),
+                    dotfile.target.display()
+                );
             }
         }
 
@@ -387,11 +396,7 @@ pub fn run(
         }
 
         for skipped in &deploy_result.skipped {
-            println!(
-                "  [skip] {} ({})",
-                skipped.target.display(),
-                skipped.reason
-            );
+            println!("  [skip] {} ({})", skipped.target.display(), skipped.reason);
         }
 
         for error in &deploy_result.errors {
@@ -433,7 +438,10 @@ pub fn run(
             }
 
             if to_install.is_empty() {
-                println!("\nall {} packages already installed", already_installed.len());
+                println!(
+                    "\nall {} packages already installed",
+                    already_installed.len()
+                );
             } else {
                 println!("\ninstalling {} packages...", to_install.len());
                 manager.install(&to_install)?;
@@ -549,8 +557,8 @@ fn merge_in_editor(source: &PathBuf, target: &PathBuf) -> anyhow::Result<bool> {
 
         let status = Command::new(&editor)
             .arg("-d")
-            .arg(&merged_path)  // target (editable)
-            .arg(source)        // source (reference)
+            .arg(&merged_path) // target (editable)
+            .arg(source) // source (reference)
             .status()?;
 
         if !status.success() {
@@ -562,9 +570,7 @@ fn merge_in_editor(source: &PathBuf, target: &PathBuf) -> anyhow::Result<bool> {
         println!("  Opening {} with target content...", editor);
         println!("  Reference source: {}", source.display());
 
-        let status = Command::new(&editor)
-            .arg(&merged_path)
-            .status()?;
+        let status = Command::new(&editor).arg(&merged_path).status()?;
 
         if !status.success() {
             let _ = std::fs::remove_file(&merged_path);
diff --git a/crates/doot-cli/src/commands/decrypt.rs b/crates/doot-cli/src/commands/decrypt.rs
index bb19bda..dcfdfe3 100644
--- a/crates/doot-cli/src/commands/decrypt.rs
+++ b/crates/doot-cli/src/commands/decrypt.rs
@@ -1,4 +1,4 @@
-use doot_core::{encryption::AgeEncryption, Config};
+use doot_core::{Config, encryption::AgeEncryption};
 use std::path::PathBuf;
 
 pub fn run(file: PathBuf, identity: Option<PathBuf>, verbose: bool) -> anyhow::Result<()> {
@@ -8,7 +8,9 @@ pub fn run(file: PathBuf, identity: Option<PathBuf>, verbose: bool) -> anyhow::R
     } else if let Ok(key) = std::env::var("DOOT_AGE_IDENTITY") {
         key
     } else if config.identity_file.exists() {
-        std::fs::read_to_string(&config.identity_file)?.trim().to_string()
+        std::fs::read_to_string(&config.identity_file)?
+            .trim()
+            .to_string()
     } else {
         anyhow::bail!(
             "no identity specified. use --identity, DOOT_AGE_IDENTITY env var, or {}",
diff --git a/crates/doot-cli/src/commands/edit.rs b/crates/doot-cli/src/commands/edit.rs
index ca78491..9489d2f 100644
--- a/crates/doot-cli/src/commands/edit.rs
+++ b/crates/doot-cli/src/commands/edit.rs
@@ -1,12 +1,12 @@
 use super::{find_config_file, parse_config, type_check};
 use doot_core::{
-    deploy::Linker,
-    state::{DeployMode, StateStore},
     Config,
+    deploy::{Linker, TemplateEngine},
+    state::{DeployMode, StateStore},
 };
 use doot_lang::Evaluator;
 use std::io::{self, Write};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 
 pub fn run(
@@ -67,7 +67,7 @@ pub fn run(
 
     if should_apply {
         if let Some(df) = dotfile {
-            apply_single(&source_file, &df.target, &df, &config, verbose)?;
+            apply_single(&source_file, &df.target, df, &config, verbose)?;
             println!("applied changes to {}", df.target.display());
         } else {
             println!("hint: run 'doot apply' to deploy changes");
@@ -109,6 +109,28 @@ fn apply_single(
 
     let mut state = StateStore::new(&config.state_file);
 
+    // Handle templates specially
+    if dotfile.template {
+        if let Some(parent) = target.parent() {
+            std::fs::create_dir_all(parent)?;
+        }
+
+        let content = std::fs::read_to_string(source)?;
+        let engine = TemplateEngine::new();
+        let rendered = engine
+            .render(&content)
+            .map_err(|e| anyhow::anyhow!("template error: {}", e))?;
+
+        std::fs::write(target, rendered)?;
+        if verbose {
+            println!("rendered {} -> {}", source.display(), target.display());
+        }
+
+        state.record_deployment_with_template(source, target, DeployMode::Copy, true);
+        state.save()?;
+        return Ok(());
+    }
+
     match deploy_mode {
         DeployMode::Link => {
             let linker = Linker::new(config.clone());
@@ -147,7 +169,7 @@ fn copy_dir_recursive(src: &PathBuf, dst: &PathBuf) -> std::io::Result<()> {
         let dst_path = dst.join(entry.file_name());
 
         if ty.is_dir() {
-            copy_dir_recursive(&src_path.into(), &dst_path)?;
+            copy_dir_recursive(&src_path, &dst_path)?;
         } else {
             std::fs::copy(&src_path, &dst_path)?;
         }
@@ -156,18 +178,17 @@ fn copy_dir_recursive(src: &PathBuf, dst: &PathBuf) -> std::io::Result<()> {
 }
 
 fn expand_tilde(path: &str) -> PathBuf {
-    if path.starts_with("~/") {
-        if let Some(home) = dirs::home_dir() {
+    if path.starts_with("~/")
+        && let Some(home) = dirs::home_dir() {
             return home.join(&path[2..]);
         }
-    }
     PathBuf::from(path)
 }
 
 fn find_source_and_dotfile<'a>(
     target: &PathBuf,
     dotfiles: &'a [doot_lang::evaluator::DotfileConfig],
-    source_dir: &PathBuf,
+    source_dir: &Path,
     state: &StateStore,
 ) -> anyhow::Result<(PathBuf, Option<&'a doot_lang::evaluator::DotfileConfig>)> {
     // Exact match with dotfile targets
diff --git a/crates/doot-cli/src/commands/encrypt.rs b/crates/doot-cli/src/commands/encrypt.rs
index 5201321..9673794 100644
--- a/crates/doot-cli/src/commands/encrypt.rs
+++ b/crates/doot-cli/src/commands/encrypt.rs
@@ -1,4 +1,4 @@
-use doot_core::{encryption::AgeEncryption, Config};
+use doot_core::{Config, encryption::AgeEncryption};
 use std::path::PathBuf;
 
 pub fn run(file: PathBuf, recipient: Option<String>, verbose: bool) -> anyhow::Result<()> {
@@ -20,7 +20,11 @@ pub fn run(file: PathBuf, recipient: Option<String>, verbose: bool) -> anyhow::R
     };
 
     if verbose {
-        println!("encrypting {} with recipient {}", file.display(), &recipient_key[..20]);
+        println!(
+            "encrypting {} with recipient {}",
+            file.display(),
+            &recipient_key[..20]
+        );
     }
 
     let mut encryption = AgeEncryption::new();
diff --git a/crates/doot-cli/src/commands/fmt.rs b/crates/doot-cli/src/commands/fmt.rs
index 6ff060f..eed0d85 100644
--- a/crates/doot-cli/src/commands/fmt.rs
+++ b/crates/doot-cli/src/commands/fmt.rs
@@ -14,13 +14,11 @@ pub fn run(config_path: Option<PathBuf>, check: bool, _verbose: bool) -> anyhow:
         } else {
             println!("{} is formatted correctly", path.display());
         }
+    } else if formatted != source {
+        std::fs::write(&path, &formatted)?;
+        println!("formatted {}", path.display());
     } else {
-        if formatted != source {
-            std::fs::write(&path, &formatted)?;
-            println!("formatted {}", path.display());
-        } else {
-            println!("{} is already formatted", path.display());
-        }
+        println!("{} is already formatted", path.display());
     }
 
     Ok(())
diff --git a/crates/doot-cli/src/commands/init.rs b/crates/doot-cli/src/commands/init.rs
index 97c819c..e04876c 100644
--- a/crates/doot-cli/src/commands/init.rs
+++ b/crates/doot-cli/src/commands/init.rs
@@ -1,5 +1,5 @@
 use doot_core::Config;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 pub fn run(path: Option<PathBuf>, verbose: bool) -> anyhow::Result<()> {
     let source_dir = path.unwrap_or_else(Config::default_source_dir);
@@ -49,7 +49,10 @@ pub fn run(path: Option<PathBuf>, verbose: bool) -> anyhow::Result<()> {
     println!("  state: {}", config.state_dir.display());
     println!();
     println!("next steps:");
-    println!("  1. add dotfiles to {}/config/", config.config_dir.display());
+    println!(
+        "  1. add dotfiles to {}/config/",
+        config.config_dir.display()
+    );
     println!("  2. edit {}/doot.doot", config.config_dir.display());
     println!("  3. run 'doot apply -n' to preview");
     println!("  4. run 'doot apply' to deploy");
@@ -57,7 +60,7 @@ pub fn run(path: Option<PathBuf>, verbose: bool) -> anyhow::Result<()> {
     Ok(())
 }
 
-fn example_config_with_source(source_dir: &PathBuf) -> String {
+fn example_config_with_source(source_dir: &Path) -> String {
     format!(
         r#"# doot.doot
 # source directory: {source_dir}
diff --git a/crates/doot-cli/src/commands/mod.rs b/crates/doot-cli/src/commands/mod.rs
index 2a3edf6..abd1a99 100644
--- a/crates/doot-cli/src/commands/mod.rs
+++ b/crates/doot-cli/src/commands/mod.rs
@@ -25,10 +25,7 @@ pub fn find_config_file(base: Option<PathBuf>) -> anyhow::Result<PathBuf> {
         anyhow::bail!("config file not found: {}", path.display());
     }
 
-    let candidates = vec![
-        PathBuf::from("doot.doot"),
-        Config::default_config_file(),
-    ];
+    let candidates = vec![PathBuf::from("doot.doot"), Config::default_config_file()];
 
     for candidate in candidates {
         if candidate.exists() {
diff --git a/crates/doot-cli/src/commands/package.rs b/crates/doot-cli/src/commands/package.rs
index 58eb6bd..2764747 100644
--- a/crates/doot-cli/src/commands/package.rs
+++ b/crates/doot-cli/src/commands/package.rs
@@ -27,14 +27,12 @@ pub fn install(config_path: Option<PathBuf>, verbose: bool) -> anyhow::Result<()
     let package_names: Vec<String> = result
         .packages
         .iter()
-        .filter_map(|p| {
-            match manager.name() {
-                "brew" => p.brew.clone().or_else(|| p.default.clone()),
-                "apt" => p.apt.clone().or_else(|| p.default.clone()),
-                "pacman" => p.pacman.clone().or_else(|| p.default.clone()),
-                "yay" => p.yay.clone().or_else(|| p.default.clone()),
-                _ => p.default.clone(),
-            }
+        .filter_map(|p| match manager.name() {
+            "brew" => p.brew.clone().or_else(|| p.default.clone()),
+            "apt" => p.apt.clone().or_else(|| p.default.clone()),
+            "pacman" => p.pacman.clone().or_else(|| p.default.clone()),
+            "yay" => p.yay.clone().or_else(|| p.default.clone()),
+            _ => p.default.clone(),
         })
         .collect();
 
diff --git a/crates/doot-cli/src/commands/rollback.rs b/crates/doot-cli/src/commands/rollback.rs
index 9c724d2..4565cbc 100644
--- a/crates/doot-cli/src/commands/rollback.rs
+++ b/crates/doot-cli/src/commands/rollback.rs
@@ -1,6 +1,6 @@
 use doot_core::{
-    state::{DeployMode, Snapshot},
     Config,
+    state::{DeployMode, Snapshot},
 };
 use std::path::PathBuf;
 
diff --git a/crates/doot-cli/src/commands/snapshot.rs b/crates/doot-cli/src/commands/snapshot.rs
index dc0f588..149e3ba 100644
--- a/crates/doot-cli/src/commands/snapshot.rs
+++ b/crates/doot-cli/src/commands/snapshot.rs
@@ -1,6 +1,6 @@
 use doot_core::{
-    state::{Snapshot, StateStore},
     Config,
+    state::{Snapshot, StateStore},
 };
 use std::path::PathBuf;
 
@@ -16,7 +16,8 @@ pub fn run(_config_path: Option<PathBuf>, name: String, verbose: bool) -> anyhow
         println!("  snapshot dir: {}", config.snapshot_dir.display());
     }
 
-    let state_content = std::fs::read_to_string(&config.state_file).unwrap_or_else(|_| "{}".to_string());
+    let state_content =
+        std::fs::read_to_string(&config.state_file).unwrap_or_else(|_| "{}".to_string());
     let state_data: doot_core::state::store::State = serde_json::from_str(&state_content)?;
 
     Snapshot::create(&name, &state_data, &config.snapshot_dir)?;
diff --git a/crates/doot-cli/src/commands/tui.rs b/crates/doot-cli/src/commands/tui.rs
index e1f14d1..df36034 100644
--- a/crates/doot-cli/src/commands/tui.rs
+++ b/crates/doot-cli/src/commands/tui.rs
@@ -2,19 +2,19 @@ use super::{find_config_file, parse_config, type_check};
 use crossterm::{
     event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyEventKind},
     execute,
-    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
+    terminal::{EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode, enable_raw_mode},
 };
 use doot_core::config::Config;
 use doot_core::deploy::Linker;
 use doot_core::state::{DeployMode, StateStore};
 use doot_lang::Evaluator;
 use ratatui::{
+    Frame, Terminal,
     backend::CrosstermBackend,
     layout::{Constraint, Direction, Layout},
     style::{Color, Modifier, Style},
     text::{Line, Span},
-    widgets::{Block, Borders, List, ListItem, ListState, Paragraph, Tabs, Gauge},
-    Frame, Terminal,
+    widgets::{Block, Borders, Gauge, List, ListItem, ListState, Paragraph, Tabs},
 };
 use std::io;
 use std::path::PathBuf;
@@ -234,14 +234,22 @@ impl App {
             Tab::Dotfiles => {
                 let len = self.dotfiles.len();
                 if len > 0 {
-                    let i = self.dotfile_state.selected().map(|i| (i + 1) % len).unwrap_or(0);
+                    let i = self
+                        .dotfile_state
+                        .selected()
+                        .map(|i| (i + 1) % len)
+                        .unwrap_or(0);
                     self.dotfile_state.select(Some(i));
                 }
             }
             Tab::Packages => {
                 let len = self.packages.len();
                 if len > 0 {
-                    let i = self.package_state.selected().map(|i| (i + 1) % len).unwrap_or(0);
+                    let i = self
+                        .package_state
+                        .selected()
+                        .map(|i| (i + 1) % len)
+                        .unwrap_or(0);
                     self.package_state.select(Some(i));
                 }
             }
@@ -257,14 +265,22 @@ impl App {
             Tab::Dotfiles => {
                 let len = self.dotfiles.len();
                 if len > 0 {
-                    let i = self.dotfile_state.selected().map(|i| if i == 0 { len - 1 } else { i - 1 }).unwrap_or(0);
+                    let i = self
+                        .dotfile_state
+                        .selected()
+                        .map(|i| if i == 0 { len - 1 } else { i - 1 })
+                        .unwrap_or(0);
                     self.dotfile_state.select(Some(i));
                 }
             }
             Tab::Packages => {
                 let len = self.packages.len();
                 if len > 0 {
-                    let i = self.package_state.selected().map(|i| if i == 0 { len - 1 } else { i - 1 }).unwrap_or(0);
+                    let i = self
+                        .package_state
+                        .selected()
+                        .map(|i| if i == 0 { len - 1 } else { i - 1 })
+                        .unwrap_or(0);
                     self.package_state.select(Some(i));
                 }
             }
@@ -278,20 +294,17 @@ impl App {
         }
         match self.tab {
             Tab::Dotfiles => {
-                if let Some(i) = self.dotfile_state.selected() {
-                    if let Some(item) = self.dotfiles.get_mut(i) {
-                        if item.status != FileStatus::Error {
+                if let Some(i) = self.dotfile_state.selected()
+                    && let Some(item) = self.dotfiles.get_mut(i)
+                        && item.status != FileStatus::Error {
                             item.selected = !item.selected;
                         }
-                    }
-                }
             }
             Tab::Packages => {
-                if let Some(i) = self.package_state.selected() {
-                    if let Some(item) = self.packages.get_mut(i) {
+                if let Some(i) = self.package_state.selected()
+                    && let Some(item) = self.packages.get_mut(i) {
                         item.selected = !item.selected;
                     }
-                }
             }
             _ => {}
         }
@@ -347,20 +360,25 @@ impl App {
         self.apply_logs.clear();
         self.log_scroll = 0;
 
-        let selected_dotfiles: Vec<_> = self.dotfiles.iter()
+        let selected_dotfiles: Vec<_> = self
+            .dotfiles
+            .iter()
             .enumerate()
             .filter(|(_, d)| d.selected && d.status != FileStatus::Error)
             .map(|(i, _)| i)
             .collect();
 
-        let selected_packages: Vec<_> = self.packages.iter()
+        let selected_packages: Vec<_> = self
+            .packages
+            .iter()
             .enumerate()
             .filter(|(_, p)| p.selected && !p.installed)
             .map(|(i, _)| i)
             .collect();
 
         if selected_dotfiles.is_empty() && selected_packages.is_empty() {
-            self.apply_logs.push(("Nothing to apply".to_string(), LogLevel::Info));
+            self.apply_logs
+                .push(("Nothing to apply".to_string(), LogLevel::Info));
             self.apply_state = ApplyState::Done;
             return;
         }
@@ -386,23 +404,26 @@ impl App {
         let has_packages = self.packages.iter().any(|p| p.selected && !p.installed);
         let has_owner = self.dotfiles.iter().any(|d| d.selected);
 
-        if has_packages {
-            if let Some(manager) = doot_core::package::detect_package_manager() {
+        if has_packages
+            && let Some(manager) = doot_core::package::detect_package_manager() {
                 return manager.needs_sudo();
             }
-        }
 
         has_owner
     }
 
     fn apply_with_sudo(&mut self) {
-        let selected_dotfiles: Vec<_> = self.dotfiles.iter()
+        let selected_dotfiles: Vec<_> = self
+            .dotfiles
+            .iter()
             .enumerate()
             .filter(|(_, d)| d.selected && d.status != FileStatus::Error)
             .map(|(i, _)| i)
             .collect();
 
-        let selected_packages: Vec<_> = self.packages.iter()
+        let selected_packages: Vec<_> = self
+            .packages
+            .iter()
             .enumerate()
             .filter(|(_, p)| p.selected && !p.installed)
             .map(|(i, _)| i)
@@ -427,12 +448,20 @@ impl App {
             };
 
             self.apply_logs.push((
-                format!("{} {} -> {}", action_name, dotfile.source.display(), target.display()),
+                format!(
+                    "{} {} -> {}",
+                    action_name,
+                    dotfile.source.display(),
+                    target.display()
+                ),
                 LogLevel::Info,
             ));
 
             let result: Result<(), String> = match dotfile.deploy_mode {
-                DeployMode::Link => linker.link(&full_source, target).map(|_| ()).map_err(|e| e.to_string()),
+                DeployMode::Link => linker
+                    .link(&full_source, target)
+                    .map(|_| ())
+                    .map_err(|e| e.to_string()),
                 DeployMode::Copy => copy_file(&full_source, target),
             };
 
@@ -448,10 +477,8 @@ impl App {
                     self.dotfiles[idx].selected = false;
                 }
                 Err(e) => {
-                    self.apply_logs.push((
-                        format!("  ✗ Failed: {}", e),
-                        LogLevel::Error,
-                    ));
+                    self.apply_logs
+                        .push((format!("  ✗ Failed: {}", e), LogLevel::Error));
                     self.dotfiles[idx].status = FileStatus::Error;
                 }
             }
@@ -471,37 +498,31 @@ impl App {
 
                 let result = if manager.needs_sudo() {
                     if let Some(ref password) = self.sudo_password {
-                        manager.install_with_sudo(&[package.name.clone()], password)
+                        manager.install_with_sudo(std::slice::from_ref(&package.name), password)
                     } else {
-                        manager.install(&[package.name.clone()])
+                        manager.install(std::slice::from_ref(&package.name))
                     }
                 } else {
-                    manager.install(&[package.name.clone()])
+                    manager.install(std::slice::from_ref(&package.name))
                 };
 
                 match result {
                     Ok(_) => {
-                        self.apply_logs.push((
-                            format!("  ✓ Installed {}", package.name),
-                            LogLevel::Success,
-                        ));
+                        self.apply_logs
+                            .push((format!("  ✓ Installed {}", package.name), LogLevel::Success));
                         self.packages[idx].installed = true;
                         self.packages[idx].selected = false;
                     }
                     Err(e) => {
-                        self.apply_logs.push((
-                            format!("  ✗ Failed: {}", e),
-                            LogLevel::Error,
-                        ));
+                        self.apply_logs
+                            .push((format!("  ✗ Failed: {}", e), LogLevel::Error));
                     }
                 }
                 self.apply_progress += 1;
             }
         } else {
-            self.apply_logs.push((
-                "No package manager available".to_string(),
-                LogLevel::Error,
-            ));
+            self.apply_logs
+                .push(("No package manager available".to_string(), LogLevel::Error));
         }
 
         self.apply_state = ApplyState::Done;
@@ -529,8 +550,8 @@ fn run_app(
     loop {
         terminal.draw(|f| ui(f, &mut app))?;
 
-        if let Event::Key(key) = event::read()? {
-            if key.kind == KeyEventKind::Press {
+        if let Event::Key(key) = event::read()?
+            && key.kind == KeyEventKind::Press {
                 match app.input_mode {
                     InputMode::Password => match key.code {
                         KeyCode::Enter => {
@@ -583,7 +604,9 @@ fn run_app(
                             _ => {}
                         },
                         ApplyState::Done => match key.code {
-                            KeyCode::Enter | KeyCode::Esc | KeyCode::Char('q') => app.dismiss_apply(),
+                            KeyCode::Enter | KeyCode::Esc | KeyCode::Char('q') => {
+                                app.dismiss_apply()
+                            }
                             KeyCode::Up | KeyCode::Char('k') => app.scroll_log_up(),
                             KeyCode::Down | KeyCode::Char('j') => app.scroll_log_down(),
                             _ => {}
@@ -591,7 +614,6 @@ fn run_app(
                     },
                 }
             }
-        }
     }
 }
 
@@ -615,7 +637,11 @@ fn ui(f: &mut Frame, app: &mut App) {
             Tab::Status => 3,
         })
         .style(Style::default().fg(Color::Cyan))
-        .highlight_style(Style::default().fg(Color::Yellow).add_modifier(Modifier::BOLD));
+        .highlight_style(
+            Style::default()
+                .fg(Color::Yellow)
+                .add_modifier(Modifier::BOLD),
+        );
     f.render_widget(tabs, chunks[0]);
 
     match app.input_mode {
@@ -652,8 +678,7 @@ fn ui(f: &mut Frame, app: &mut App) {
                 } else {
                     "Applying..."
                 };
-                let help = Paragraph::new(help_text)
-                    .block(Block::default().borders(Borders::ALL));
+                let help = Paragraph::new(help_text).block(Block::default().borders(Borders::ALL));
                 f.render_widget(help, chunks[2]);
             }
         },
@@ -663,10 +688,7 @@ fn ui(f: &mut Frame, app: &mut App) {
 fn render_apply_progress(f: &mut Frame, app: &App, area: ratatui::layout::Rect) {
     let chunks = Layout::default()
         .direction(Direction::Vertical)
-        .constraints([
-            Constraint::Length(3),
-            Constraint::Min(0),
-        ])
+        .constraints([Constraint::Length(3), Constraint::Min(0)])
         .split(area);
 
     // Progress bar
@@ -697,7 +719,10 @@ fn render_apply_progress(f: &mut Frame, app: &App, area: ratatui::layout::Rect)
                 LogLevel::Success => Color::Green,
                 LogLevel::Error => Color::Red,
             };
-            ListItem::new(Line::from(Span::styled(msg.as_str(), Style::default().fg(color))))
+            ListItem::new(Line::from(Span::styled(
+                msg.as_str(),
+                Style::default().fg(color),
+            )))
         })
         .collect();
 
@@ -707,8 +732,7 @@ fn render_apply_progress(f: &mut Frame, app: &App, area: ratatui::layout::Rect)
         "Applying..."
     };
 
-    let list = List::new(items)
-        .block(Block::default().borders(Borders::ALL).title(title));
+    let list = List::new(items).block(Block::default().borders(Borders::ALL).title(title));
     f.render_widget(list, chunks[1]);
 }
 
@@ -782,35 +806,63 @@ fn render_secrets(f: &mut Frame, area: ratatui::layout::Rect) {
 }
 
 fn render_status(f: &mut Frame, app: &App, area: ratatui::layout::Rect) {
-    let synced = app.dotfiles.iter().filter(|d| matches!(d.status, FileStatus::Synced)).count();
-    let pending = app.dotfiles.iter().filter(|d| matches!(d.status, FileStatus::Pending)).count();
-    let modified = app.dotfiles.iter().filter(|d| matches!(d.status, FileStatus::Modified)).count();
-    let errors = app.dotfiles.iter().filter(|d| matches!(d.status, FileStatus::Error)).count();
+    let synced = app
+        .dotfiles
+        .iter()
+        .filter(|d| matches!(d.status, FileStatus::Synced))
+        .count();
+    let pending = app
+        .dotfiles
+        .iter()
+        .filter(|d| matches!(d.status, FileStatus::Pending))
+        .count();
+    let modified = app
+        .dotfiles
+        .iter()
+        .filter(|d| matches!(d.status, FileStatus::Modified))
+        .count();
+    let errors = app
+        .dotfiles
+        .iter()
+        .filter(|d| matches!(d.status, FileStatus::Error))
+        .count();
     let installed = app.packages.iter().filter(|p| p.installed).count();
 
     let text = format!(
         "Source: {}\n\nDotfiles:\n  Synced: {}\n  Pending: {}\n  Modified: {}\n  Errors: {}\n\nPackages:\n  Installed: {}/{}",
         app.source_dir.display(),
-        synced, pending, modified, errors, installed, app.packages.len()
+        synced,
+        pending,
+        modified,
+        errors,
+        installed,
+        app.packages.len()
     );
 
-    let paragraph = Paragraph::new(text)
-        .block(Block::default().borders(Borders::ALL).title("Status"));
+    let paragraph =
+        Paragraph::new(text).block(Block::default().borders(Borders::ALL).title("Status"));
     f.render_widget(paragraph, area);
 }
 
 fn render_sudo_prompt(f: &mut Frame, area: ratatui::layout::Rect) {
-    let text = "Package installation requires sudo privileges.\n\nDo you want to enter your password?";
-    let paragraph = Paragraph::new(text)
-        .block(Block::default().borders(Borders::ALL).title("Sudo Required"));
+    let text =
+        "Package installation requires sudo privileges.\n\nDo you want to enter your password?";
+    let paragraph = Paragraph::new(text).block(
+        Block::default()
+            .borders(Borders::ALL)
+            .title("Sudo Required"),
+    );
     f.render_widget(paragraph, area);
 }
 
 fn render_password_input(f: &mut Frame, app: &App, area: ratatui::layout::Rect) {
     let masked: String = "*".repeat(app.password_input.len());
     let text = format!("Password: {}_", masked);
-    let paragraph = Paragraph::new(text)
-        .block(Block::default().borders(Borders::ALL).title("Enter sudo password"));
+    let paragraph = Paragraph::new(text).block(
+        Block::default()
+            .borders(Borders::ALL)
+            .title("Enter sudo password"),
+    );
     f.render_widget(paragraph, area);
 }
 
@@ -837,7 +889,7 @@ fn copy_dir_recursive(src: &PathBuf, dst: &PathBuf) -> std::io::Result<()> {
         let dst_path = dst.join(entry.file_name());
 
         if ty.is_dir() {
-            copy_dir_recursive(&src_path.into(), &dst_path)?;
+            copy_dir_recursive(&src_path, &dst_path)?;
         } else {
             std::fs::copy(&src_path, &dst_path)?;
         }
diff --git a/crates/doot-cli/src/main.rs b/crates/doot-cli/src/main.rs
index c51af21..6a3e8f8 100644
--- a/crates/doot-cli/src/main.rs
+++ b/crates/doot-cli/src/main.rs
@@ -118,9 +118,7 @@ fn main() -> anyhow::Result<()> {
         Commands::Encrypt { file, recipient } => {
             commands::encrypt::run(file, recipient, cli.verbose)
         }
-        Commands::Decrypt { file, identity } => {
-            commands::decrypt::run(file, identity, cli.verbose)
-        }
+        Commands::Decrypt { file, identity } => commands::decrypt::run(file, identity, cli.verbose),
         Commands::Package { action } => match action {
             PackageAction::Install => commands::package::install(cli.config, cli.verbose),
             PackageAction::Update => commands::package::update(cli.verbose),
diff --git a/crates/doot-cli/tests/e2e.rs b/crates/doot-cli/tests/e2e.rs
index 1f2b876..f60b9f0 100644
--- a/crates/doot-cli/tests/e2e.rs
+++ b/crates/doot-cli/tests/e2e.rs
@@ -72,18 +72,29 @@ fn test_init_creates_structure() {
 
     assert!(output.status.success(), "init failed: {:?}", output);
     assert!(sandbox.config_file().exists(), "config file not created");
-    assert!(sandbox.config_dir().join("config").exists(), "config dir not created");
-    assert!(sandbox.state_dir().join("backups").exists(), "backups dir not created");
-    assert!(sandbox.state_dir().join("snapshots").exists(), "snapshots dir not created");
+    assert!(
+        sandbox.config_dir().join("config").exists(),
+        "config dir not created"
+    );
+    assert!(
+        sandbox.state_dir().join("backups").exists(),
+        "backups dir not created"
+    );
+    assert!(
+        sandbox.state_dir().join("snapshots").exists(),
+        "snapshots dir not created"
+    );
 }
 
 #[test]
 fn test_check_valid_config() {
     let sandbox = Sandbox::new("check-valid");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 package: "ripgrep"
 package: "fd"
-"#);
+"#,
+    );
 
     let output = sandbox.run(&["check"]);
     assert!(output.status.success(), "check failed: {:?}", output);
@@ -92,11 +103,13 @@ package: "fd"
 #[test]
 fn test_apply_dry_run() {
     let sandbox = Sandbox::new("apply-dry");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/test.conf"
     target = "~/.config/test/test.conf"
-"#);
+"#,
+    );
     sandbox.write_source("config/test.conf", "test content");
 
     let output = sandbox.run(&["apply", "-n"]);
@@ -109,12 +122,14 @@ dotfile:
 #[test]
 fn test_apply_creates_symlink() {
     let sandbox = Sandbox::new("apply-symlink");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/app.conf"
     target = "~/.config/app/app.conf"
     deploy = "link"
-"#);
+"#,
+    );
     sandbox.write_source("config/app.conf", "app config content");
 
     let output = sandbox.run(&["apply"]);
@@ -147,17 +162,22 @@ fn test_apply_unchanged_on_rerun() {
 
     // Second apply should succeed (symlink already exists and points correctly)
     let target = sandbox.path.join(".config/app/app.conf");
-    assert!(target.is_symlink(), "target should still be symlink after second apply");
+    assert!(
+        target.is_symlink(),
+        "target should still be symlink after second apply"
+    );
 }
 
 #[test]
 fn test_apply_creates_copy() {
     let sandbox = Sandbox::new("apply-copy");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/app.conf"
     target = "~/.config/app/app.conf"
-"#);
+"#,
+    );
     sandbox.write_source("config/app.conf", "app config content");
 
     let output = sandbox.run(&["apply"]);
@@ -165,7 +185,10 @@ dotfile:
 
     let target = sandbox.path.join(".config/app/app.conf");
     assert!(target.exists(), "target should exist");
-    assert!(!target.is_symlink(), "target should be a copy, not a symlink");
+    assert!(
+        !target.is_symlink(),
+        "target should be a copy, not a symlink"
+    );
 
     let content = std::fs::read_to_string(&target).unwrap();
     assert_eq!(content, "app config content", "content should match source");
@@ -193,11 +216,13 @@ fn test_apply_copy_unchanged_on_rerun() {
 #[test]
 fn test_status_shows_state() {
     let sandbox = Sandbox::new("status");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/app.conf"
     target = "~/.config/app/app.conf"
-"#);
+"#,
+    );
     sandbox.write_source("config/app.conf", "content");
     sandbox.run(&["apply"]);
 
@@ -208,16 +233,22 @@ dotfile:
 #[test]
 fn test_snapshot_and_rollback() {
     let sandbox = Sandbox::new("snapshot");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/app.conf"
     target = "~/.config/app/app.conf"
-"#);
+"#,
+    );
     sandbox.write_source("config/app.conf", "v1");
     sandbox.run(&["apply"]);
 
     let snap_output = sandbox.run(&["snapshot", "v1"]);
-    assert!(snap_output.status.success(), "snapshot failed: {:?}", snap_output);
+    assert!(
+        snap_output.status.success(),
+        "snapshot failed: {:?}",
+        snap_output
+    );
 
     let snapshot_file = sandbox.state_dir().join("snapshots/v1.json");
     assert!(snapshot_file.exists(), "snapshot file not created");
@@ -240,7 +271,10 @@ fn test_dotfile_with_when_condition() {
     assert!(output.status.success(), "apply failed: {:?}", output);
 
     let target = sandbox.path.join(".config/test.conf");
-    assert!(target.exists(), "file should be deployed when condition is true");
+    assert!(
+        target.exists(),
+        "file should be deployed when condition is true"
+    );
 }
 
 #[test]
@@ -259,17 +293,22 @@ fn test_dotfile_when_false_skips() {
     assert!(output.status.success(), "apply failed: {:?}", output);
 
     let target = sandbox.path.join(".config/skip.conf");
-    assert!(!target.exists(), "file should NOT be deployed when condition is false");
+    assert!(
+        !target.exists(),
+        "file should NOT be deployed when condition is false"
+    );
 }
 
 #[test]
 fn test_diff_shows_changes() {
     let sandbox = Sandbox::new("diff");
-    sandbox.write_config(r#"
+    sandbox.write_config(
+        r#"
 dotfile:
     source = "config/app.conf"
     target = "~/.config/app/app.conf"
-"#);
+"#,
+    );
     sandbox.write_source("config/app.conf", "new content");
 
     let target_dir = sandbox.path.join(".config/app");
diff --git a/crates/doot-core/Cargo.toml b/crates/doot-core/Cargo.toml
index 21f0da9..b12daed 100644
--- a/crates/doot-core/Cargo.toml
+++ b/crates/doot-core/Cargo.toml
@@ -22,3 +22,5 @@ anyhow.workspace = true
 hostname = "0.4"
 regex-lite = "0.1"
 glob = "0.3"
+minijinja = { version = "2", features = ["builtins"] }
+which = "7"
diff --git a/crates/doot-core/src/config.rs b/crates/doot-core/src/config.rs
index cc8462c..da8bc2b 100644
--- a/crates/doot-core/src/config.rs
+++ b/crates/doot-core/src/config.rs
@@ -72,7 +72,7 @@ impl Config {
             return PathBuf::from(doot_home).join(".local/state/doot");
         }
         dirs::state_dir()
-            .or_else(|| dirs::data_local_dir())
+            .or_else(dirs::data_local_dir)
             .unwrap_or_else(|| Self::home_dir().join(".local/state"))
             .join("doot")
     }
diff --git a/crates/doot-core/src/deploy/mod.rs b/crates/doot-core/src/deploy/mod.rs
index aab79fd..cb2b9f3 100644
--- a/crates/doot-core/src/deploy/mod.rs
+++ b/crates/doot-core/src/deploy/mod.rs
@@ -5,8 +5,8 @@ pub mod linker;
 pub mod template;
 
 use crate::config::Config;
-use crate::state::store::DeployMode;
 use crate::state::StateStore;
+use crate::state::store::DeployMode;
 use doot_lang::evaluator::DotfileConfig;
 use glob::Pattern;
 use std::path::{Path, PathBuf};
@@ -181,12 +181,11 @@ impl Deployer {
         }
 
         // For files or link mode, handle as before
-        if target.exists() && !target.is_symlink() {
-            if !self.config.dry_run {
+        if target.exists() && !target.is_symlink()
+            && !self.config.dry_run {
                 self.backup_existing(target)?;
                 std::fs::remove_file(target)?;
             }
-        }
 
         let action = if dotfile.template {
             self.deploy_template(&source, target)?
@@ -198,18 +197,21 @@ impl Deployer {
         };
 
         // Set permissions if specified (only for copy mode, symlinks inherit from source)
-        if !dotfile.permissions.is_empty() && deploy_mode == DeployMode::Copy && !self.config.dry_run {
+        if !dotfile.permissions.is_empty()
+            && deploy_mode == DeployMode::Copy
+            && !self.config.dry_run
+        {
             apply_permissions(target, &dotfile.permissions)?;
         }
 
         // Set owner if specified
-        if let Some(ref owner) = dotfile.owner {
-            if !self.config.dry_run {
+        if let Some(ref owner) = dotfile.owner
+            && !self.config.dry_run {
                 set_owner(target, owner)?;
             }
-        }
 
-        self.state.record_deployment(&source, target, deploy_mode);
+        self.state
+            .record_deployment_with_template(&source, target, deploy_mode, dotfile.template);
 
         Ok(DeployedFile {
             source: source.clone(),
@@ -242,9 +244,7 @@ impl Deployer {
 
         for (src_file, tgt_file, status) in changed_files {
             match status {
-                SyncStatus::NotDeployed
-                | SyncStatus::TargetMissing
-                | SyncStatus::SourceChanged => {
+                SyncStatus::NotDeployed | SyncStatus::TargetMissing | SyncStatus::SourceChanged => {
                     // Copy from source to target
                     if !self.config.dry_run {
                         if let Some(parent) = tgt_file.parent() {
@@ -264,12 +264,14 @@ impl Deployer {
                         any_updated = true;
                     }
 
-                    self.state.record_deployment(&src_file, &tgt_file, deploy_mode);
+                    self.state
+                        .record_deployment(&src_file, &tgt_file, deploy_mode);
                 }
                 SyncStatus::TargetChanged => {
                     // Target changed but source didn't - keep target, just update state
                     // This is like keeping local changes in git
-                    self.state.record_deployment(&src_file, &tgt_file, deploy_mode);
+                    self.state
+                        .record_deployment(&src_file, &tgt_file, deploy_mode);
                 }
                 SyncStatus::Conflict => {
                     // Real conflict - user already chose "use source" at directory level
@@ -284,7 +286,8 @@ impl Deployer {
                         }
                     }
                     any_updated = true;
-                    self.state.record_deployment(&src_file, &tgt_file, deploy_mode);
+                    self.state
+                        .record_deployment(&src_file, &tgt_file, deploy_mode);
                 }
                 SyncStatus::SourceMissing => {
                     // File was deleted from source, remove from target
@@ -301,11 +304,10 @@ impl Deployer {
         }
 
         // Set owner if specified (for entire directory)
-        if let Some(ref owner) = dotfile.owner {
-            if !self.config.dry_run {
+        if let Some(ref owner) = dotfile.owner
+            && !self.config.dry_run {
                 set_owner(target, owner)?;
             }
-        }
 
         // Also record the directory-level deployment for sync status checks
         self.state.record_deployment(source, target, deploy_mode);
@@ -340,21 +342,19 @@ impl Deployer {
         match base_mode {
             DeployMode::Copy => {
                 for pattern in &dotfile.link_patterns {
-                    if let Ok(p) = Pattern::new(pattern) {
-                        if p.matches(&relative_path) {
+                    if let Ok(p) = Pattern::new(pattern)
+                        && p.matches(&relative_path) {
                             return DeployMode::Link;
                         }
-                    }
                 }
                 DeployMode::Copy
             }
             DeployMode::Link => {
                 for pattern in &dotfile.copy_patterns {
-                    if let Ok(p) = Pattern::new(pattern) {
-                        if p.matches(&relative_path) {
+                    if let Ok(p) = Pattern::new(pattern)
+                        && p.matches(&relative_path) {
                             return DeployMode::Copy;
                         }
-                    }
                 }
                 DeployMode::Link
             }
@@ -523,12 +523,11 @@ fn apply_permissions_recursive(
                         break;
                     }
                     PermissionRule::Pattern { pattern, mode } => {
-                        if let Ok(p) = Pattern::new(pattern) {
-                            if p.matches(&relative) {
+                        if let Ok(p) = Pattern::new(pattern)
+                            && p.matches(&relative) {
                                 set_file_permissions(&path, *mode)?;
                                 break;
                             }
-                        }
                     }
                 }
             }
@@ -577,7 +576,10 @@ fn set_owner(path: &Path, owner: &str) -> Result<(), DeployError> {
 
     if !sudo_output.status.success() {
         let stderr = String::from_utf8_lossy(&sudo_output.stderr);
-        return Err(DeployError::ChownFailed(path.to_path_buf(), stderr.to_string()));
+        return Err(DeployError::ChownFailed(
+            path.to_path_buf(),
+            stderr.to_string(),
+        ));
     }
 
     Ok(())
diff --git a/crates/doot-core/src/deploy/template.rs b/crates/doot-core/src/deploy/template.rs
index 07de681..09af521 100644
--- a/crates/doot-core/src/deploy/template.rs
+++ b/crates/doot-core/src/deploy/template.rs
@@ -1,68 +1,47 @@
-//! Template rendering for dotfiles.
+//! Template rendering for dotfiles using MiniJinja.
 
+use minijinja::{Environment, Value};
 use std::collections::HashMap;
+use std::path::PathBuf;
 
-/// Renders templates with variable substitution.
+/// Renders templates with Jinja2-style syntax.
 pub struct TemplateEngine {
-    variables: HashMap<String, String>,
+    env: Environment<'static>,
+    variables: HashMap<String, Value>,
 }
 
 impl TemplateEngine {
-    /// Creates a new engine with default variables.
+    /// Creates a new engine with default variables and functions.
     pub fn new() -> Self {
-        let mut variables = HashMap::new();
+        let mut env = Environment::new();
 
-        if let Some(home) = dirs::home_dir() {
-            variables.insert("home".to_string(), home.display().to_string());
-        }
-        if let Some(config) = dirs::config_dir() {
-            variables.insert("config_dir".to_string(), config.display().to_string());
-        }
-        if let Some(data) = dirs::data_dir() {
-            variables.insert("data_dir".to_string(), data.display().to_string());
-        }
-        if let Some(cache) = dirs::cache_dir() {
-            variables.insert("cache_dir".to_string(), cache.display().to_string());
-        }
+        // Register custom functions
+        register_functions(&mut env);
 
-        variables.insert("os".to_string(), std::env::consts::OS.to_string());
-        variables.insert("arch".to_string(), std::env::consts::ARCH.to_string());
+        // Build default variables
+        let variables = build_default_variables();
 
-        if let Ok(hostname) = hostname::get() {
-            variables.insert("hostname".to_string(), hostname.to_string_lossy().to_string());
-        }
-
-        for (key, value) in std::env::vars() {
-            variables.insert(format!("env.{}", key), value);
-        }
-
-        Self { variables }
+        Self { env, variables }
     }
 
     /// Sets a template variable.
-    pub fn set_variable(&mut self, key: String, value: String) {
-        self.variables.insert(key, value);
+    pub fn set_variable(&mut self, key: String, value: impl Into<Value>) {
+        self.variables.insert(key, value.into());
     }
 
     /// Renders a template string.
     pub fn render(&self, template: &str) -> Result<String, String> {
-        let mut result = template.to_string();
+        // Add template to environment
+        let tmpl = self
+            .env
+            .template_from_str(template)
+            .map_err(|e| format!("template parse error: {}", e))?;
 
-        for (key, value) in &self.variables {
-            result = result.replace(&format!("{{{{ {} }}}}", key), value);
-            result = result.replace(&format!("{{{{{}}}}}", key), value);
-        }
+        // Build context from variables
+        let ctx = Value::from_iter(self.variables.clone());
 
-        let re = regex_lite::Regex::new(r"\{\{[^}]+\}\}").unwrap();
-        if re.is_match(&result) {
-            let unresolved: Vec<&str> = re.find_iter(&result).map(|m| m.as_str()).collect();
-            return Err(format!(
-                "unresolved template variables: {}",
-                unresolved.join(", ")
-            ));
-        }
-
-        Ok(result)
+        tmpl.render(ctx)
+            .map_err(|e| format!("template render error: {}", e))
     }
 }
 
@@ -71,3 +50,532 @@ impl Default for TemplateEngine {
         Self::new()
     }
 }
+
+/// Builds the default template variables.
+fn build_default_variables() -> HashMap<String, Value> {
+    let mut vars = HashMap::new();
+
+    // Directory paths
+    if let Some(home) = dirs::home_dir() {
+        vars.insert("home".to_string(), Value::from(home.display().to_string()));
+    }
+    if let Some(config) = dirs::config_dir() {
+        vars.insert(
+            "config_dir".to_string(),
+            Value::from(config.display().to_string()),
+        );
+    }
+    if let Some(data) = dirs::data_dir() {
+        vars.insert(
+            "data_dir".to_string(),
+            Value::from(data.display().to_string()),
+        );
+    }
+    if let Some(cache) = dirs::cache_dir() {
+        vars.insert(
+            "cache_dir".to_string(),
+            Value::from(cache.display().to_string()),
+        );
+    }
+
+    // System info
+    vars.insert("os".to_string(), Value::from(std::env::consts::OS));
+    vars.insert("arch".to_string(), Value::from(std::env::consts::ARCH));
+
+    if let Ok(hostname) = hostname::get() {
+        vars.insert(
+            "hostname".to_string(),
+            Value::from(hostname.to_string_lossy().to_string()),
+        );
+    }
+
+    // Detect Linux distro
+    if std::env::consts::OS == "linux"
+        && let Some(distro) = detect_distro() {
+            vars.insert("distro".to_string(), Value::from(distro));
+        }
+
+    // Environment variables as a nested object
+    let env_vars: HashMap<String, Value> =
+        std::env::vars().map(|(k, v)| (k, Value::from(v))).collect();
+    vars.insert("env".to_string(), Value::from_iter(env_vars));
+
+    vars
+}
+
+/// Registers custom functions available in templates.
+fn register_functions(env: &mut Environment<'static>) {
+    // ===== File System Functions =====
+
+    // file_exists(path) - check if a file or directory exists
+    env.add_function("file_exists", |path: String| -> bool {
+        std::path::Path::new(&expand_path(&path)).exists()
+    });
+
+    // dir_exists(path) - check if a directory exists
+    env.add_function("dir_exists", |path: String| -> bool {
+        std::path::Path::new(&expand_path(&path)).is_dir()
+    });
+
+    // is_symlink(path) - check if path is a symlink
+    env.add_function("is_symlink", |path: String| -> bool {
+        std::path::Path::new(&expand_path(&path)).is_symlink()
+    });
+
+    // read_link(path) - get symlink target
+    env.add_function("read_link", |path: String| -> String {
+        std::fs::read_link(expand_path(&path))
+            .map(|p| p.display().to_string())
+            .unwrap_or_default()
+    });
+
+    // read_file(path) - read file contents (returns empty string on error)
+    env.add_function("read_file", |path: String| -> String {
+        std::fs::read_to_string(expand_path(&path)).unwrap_or_default()
+    });
+
+    // read_file_lines(path) - read file as list of lines
+    env.add_function("read_file_lines", |path: String| -> Vec<String> {
+        std::fs::read_to_string(expand_path(&path))
+            .map(|s| s.lines().map(|l| l.to_string()).collect())
+            .unwrap_or_default()
+    });
+
+    // list_dir(path) - list directory contents
+    env.add_function("list_dir", |path: String| -> Vec<String> {
+        std::fs::read_dir(expand_path(&path))
+            .map(|entries| {
+                entries
+                    .filter_map(|e| e.ok())
+                    .map(|e| e.path().display().to_string())
+                    .collect()
+            })
+            .unwrap_or_default()
+    });
+
+    // glob(pattern) - find files matching glob pattern
+    env.add_function("glob", |pattern: String| -> Vec<String> {
+        glob::glob(&pattern)
+            .map(|paths| {
+                paths
+                    .filter_map(|p| p.ok())
+                    .map(|p| p.display().to_string())
+                    .collect()
+            })
+            .unwrap_or_default()
+    });
+
+    // temp_dir() - get temp directory path
+    env.add_function("temp_dir", || -> String {
+        std::env::temp_dir().display().to_string()
+    });
+
+    // ===== Path Functions =====
+
+    // path_join(a, b, ...) - join path components
+    env.add_function("path_join", |parts: Vec<String>| -> String {
+        let mut result = PathBuf::new();
+        for part in parts {
+            result.push(part);
+        }
+        result.display().to_string()
+    });
+
+    // path_parent(path) - get parent directory
+    env.add_function("path_parent", |path: String| -> String {
+        std::path::Path::new(&path)
+            .parent()
+            .map(|p| p.display().to_string())
+            .unwrap_or_default()
+    });
+
+    // path_filename(path) - get filename component
+    env.add_function("path_filename", |path: String| -> String {
+        std::path::Path::new(&path)
+            .file_name()
+            .map(|s| s.to_string_lossy().to_string())
+            .unwrap_or_default()
+    });
+
+    // path_extension(path) - get file extension
+    env.add_function("path_extension", |path: String| -> String {
+        std::path::Path::new(&path)
+            .extension()
+            .map(|s| s.to_string_lossy().to_string())
+            .unwrap_or_default()
+    });
+
+    // config_path(app) - get config directory for an app
+    env.add_function("config_path", |app: String| -> String {
+        dirs::config_dir()
+            .map(|p| p.join(&app).display().to_string())
+            .unwrap_or_default()
+    });
+
+    // ===== Command/Process Functions =====
+
+    // command_exists(cmd) - check if a command is available in PATH
+    env.add_function("command_exists", |cmd: String| -> bool {
+        which::which(&cmd).is_ok()
+    });
+
+    // which(cmd) - get full path to command (empty string if not found)
+    env.add_function("which", |cmd: String| -> String {
+        which::which(&cmd)
+            .map(|p| p.display().to_string())
+            .unwrap_or_default()
+    });
+
+    // shell(cmd) - execute a shell command and return output (trimmed)
+    env.add_function("shell", |cmd: String| -> String {
+        std::process::Command::new("sh")
+            .arg("-c")
+            .arg(&cmd)
+            .output()
+            .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
+            .unwrap_or_default()
+    });
+
+    // shell_status(cmd) - execute command and return exit status
+    env.add_function("shell_status", |cmd: String| -> i32 {
+        std::process::Command::new("sh")
+            .arg("-c")
+            .arg(&cmd)
+            .status()
+            .map(|s| s.code().unwrap_or(-1))
+            .unwrap_or(-1)
+    });
+
+    // ===== Environment Functions =====
+
+    // get_env(name, default?) - get environment variable with optional default
+    env.add_function(
+        "get_env",
+        |name: String, default: Option<String>| -> String {
+            std::env::var(&name).unwrap_or_else(|_| default.unwrap_or_default())
+        },
+    );
+
+    // ===== OS Detection Functions =====
+
+    // is_macos() - convenience check
+    env.add_function("is_macos", || -> bool { std::env::consts::OS == "macos" });
+
+    // is_linux() - convenience check
+    env.add_function("is_linux", || -> bool { std::env::consts::OS == "linux" });
+
+    // is_windows() - convenience check
+    env.add_function("is_windows", || -> bool {
+        std::env::consts::OS == "windows"
+    });
+
+    // is_arch() - check if running Arch Linux
+    env.add_function("is_arch", || -> bool {
+        detect_distro().map(|d| d == "arch").unwrap_or(false)
+    });
+
+    // is_ubuntu() - check if running Ubuntu
+    env.add_function("is_ubuntu", || -> bool {
+        detect_distro().map(|d| d == "ubuntu").unwrap_or(false)
+    });
+
+    // is_fedora() - check if running Fedora
+    env.add_function("is_fedora", || -> bool {
+        detect_distro().map(|d| d == "fedora").unwrap_or(false)
+    });
+
+    // is_debian() - check if running Debian
+    env.add_function("is_debian", || -> bool {
+        detect_distro().map(|d| d == "debian").unwrap_or(false)
+    });
+
+    // is_nixos() - check if running NixOS
+    env.add_function("is_nixos", || -> bool {
+        detect_distro().map(|d| d == "nixos").unwrap_or(false)
+    });
+
+    // is_nix() - check if nix package manager is available
+    env.add_function("is_nix", || -> bool {
+        // Check for nix command or /nix directory
+        which::which("nix").is_ok() || std::path::Path::new("/nix").exists()
+    });
+
+    // hostname_matches(pattern) - check if hostname matches a pattern
+    env.add_function("hostname_matches", |pattern: String| -> bool {
+        if let Ok(hostname) = hostname::get() {
+            let hostname = hostname.to_string_lossy();
+            if pattern.contains('*') {
+                // Simple glob matching
+                let regex_pattern = format!("^{}$", pattern.replace('*', ".*"));
+                regex_lite::Regex::new(&regex_pattern)
+                    .map(|re| re.is_match(&hostname))
+                    .unwrap_or(false)
+            } else {
+                hostname == pattern
+            }
+        } else {
+            false
+        }
+    });
+
+    // ===== Parsing Functions =====
+
+    // from_json(str) - parse JSON string into object
+    env.add_function("from_json", |s: String| -> Value {
+        serde_json::from_str::<serde_json::Value>(&s)
+            .map(|v| json_to_minijinja(&v))
+            .unwrap_or(Value::UNDEFINED)
+    });
+
+    // from_toml(str) - parse TOML string into object
+    env.add_function("from_toml", |s: String| -> Value {
+        toml::from_str::<toml::Value>(&s)
+            .map(|v| toml_to_minijinja(&v))
+            .unwrap_or(Value::UNDEFINED)
+    });
+
+    // ===== Crypto Functions =====
+
+    // hash_str(str) - hash a string using BLAKE3
+    env.add_function("hash_str", |s: String| -> String {
+        blake3::hash(s.as_bytes()).to_hex().to_string()
+    });
+
+    // hash_file(path) - hash a file using BLAKE3
+    env.add_function("hash_file", |path: String| -> String {
+        std::fs::read(expand_path(&path))
+            .map(|content| blake3::hash(&content).to_hex().to_string())
+            .unwrap_or_default()
+    });
+
+    // ===== String Functions =====
+
+    // starts_with(str, prefix) - check if string starts with prefix
+    env.add_function("starts_with", |s: String, prefix: String| -> bool {
+        s.starts_with(&prefix)
+    });
+
+    // ends_with(str, suffix) - check if string ends with suffix
+    env.add_function("ends_with", |s: String, suffix: String| -> bool {
+        s.ends_with(&suffix)
+    });
+
+    // contains(str, needle) - check if string contains needle
+    env.add_function("contains", |s: String, needle: String| -> bool {
+        s.contains(&needle)
+    });
+}
+
+/// Expands ~ to home directory in paths.
+fn expand_path(s: &str) -> PathBuf {
+    if let Some(stripped) = s.strip_prefix('~') {
+        let home = dirs::home_dir().unwrap_or_default();
+        home.join(stripped.strip_prefix('/').unwrap_or(stripped))
+    } else {
+        PathBuf::from(s)
+    }
+}
+
+/// Detects the Linux distribution.
+fn detect_distro() -> Option<String> {
+    if std::env::consts::OS != "linux" {
+        return None;
+    }
+    // Try /etc/os-release first
+    if let Ok(content) = std::fs::read_to_string("/etc/os-release") {
+        for line in content.lines() {
+            if let Some(id) = line.strip_prefix("ID=") {
+                return Some(id.trim_matches('"').to_string());
+            }
+        }
+    }
+    None
+}
+
+/// Converts serde_json::Value to minijinja::Value.
+fn json_to_minijinja(json: &serde_json::Value) -> Value {
+    match json {
+        serde_json::Value::Null => Value::from(()),
+        serde_json::Value::Bool(b) => Value::from(*b),
+        serde_json::Value::Number(n) => {
+            if let Some(i) = n.as_i64() {
+                Value::from(i)
+            } else if let Some(f) = n.as_f64() {
+                Value::from(f)
+            } else {
+                Value::from(())
+            }
+        }
+        serde_json::Value::String(s) => Value::from(s.clone()),
+        serde_json::Value::Array(arr) => {
+            Value::from(arr.iter().map(json_to_minijinja).collect::<Vec<_>>())
+        }
+        serde_json::Value::Object(obj) => {
+            let map: std::collections::BTreeMap<String, Value> = obj
+                .iter()
+                .map(|(k, v)| (k.clone(), json_to_minijinja(v)))
+                .collect();
+            Value::from_iter(map)
+        }
+    }
+}
+
+/// Converts toml::Value to minijinja::Value.
+fn toml_to_minijinja(toml: &toml::Value) -> Value {
+    match toml {
+        toml::Value::Boolean(b) => Value::from(*b),
+        toml::Value::Integer(i) => Value::from(*i),
+        toml::Value::Float(f) => Value::from(*f),
+        toml::Value::String(s) => Value::from(s.clone()),
+        toml::Value::Array(arr) => {
+            Value::from(arr.iter().map(toml_to_minijinja).collect::<Vec<_>>())
+        }
+        toml::Value::Table(table) => {
+            let map: std::collections::BTreeMap<String, Value> = table
+                .iter()
+                .map(|(k, v)| (k.clone(), toml_to_minijinja(v)))
+                .collect();
+            Value::from_iter(map)
+        }
+        toml::Value::Datetime(dt) => Value::from(dt.to_string()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_simple_variable() {
+        let engine = TemplateEngine::new();
+        let result = engine.render("Hello {{ os }}!").unwrap();
+        assert!(result.contains("linux") || result.contains("macos") || result.contains("windows"));
+    }
+
+    #[test]
+    fn test_if_else() {
+        let engine = TemplateEngine::new();
+        let template = r#"{% if os == "linux" %}Linux{% else %}Other{% endif %}"#;
+        let result = engine.render(template).unwrap();
+
+        if std::env::consts::OS == "linux" {
+            assert_eq!(result, "Linux");
+        } else {
+            assert_eq!(result, "Other");
+        }
+    }
+
+    #[test]
+    fn test_command_exists() {
+        let engine = TemplateEngine::new();
+        // 'sh' should exist on all Unix systems
+        let template = r#"{% if command_exists("sh") %}yes{% else %}no{% endif %}"#;
+        let result = engine.render(template).unwrap();
+        assert_eq!(result, "yes");
+    }
+
+    #[test]
+    fn test_which() {
+        let engine = TemplateEngine::new();
+        let result = engine.render("{{ which('sh') }}").unwrap();
+        assert!(result.contains("sh"));
+    }
+
+    #[test]
+    fn test_env_access() {
+        // SAFETY: This is a test running in isolation
+        unsafe { std::env::set_var("DOOT_TEST_VAR", "test_value") };
+        let engine = TemplateEngine::new();
+        let result = engine.render("{{ env.DOOT_TEST_VAR }}").unwrap();
+        assert_eq!(result, "test_value");
+    }
+
+    #[test]
+    fn test_filters() {
+        let engine = TemplateEngine::new();
+        let result = engine.render("{{ 'hello' | upper }}").unwrap();
+        assert_eq!(result, "HELLO");
+    }
+
+    #[test]
+    fn test_for_loop() {
+        let mut engine = TemplateEngine::new();
+        engine.set_variable("items".to_string(), Value::from(vec!["a", "b", "c"]));
+        let result = engine
+            .render("{% for i in items %}{{ i }}{% endfor %}")
+            .unwrap();
+        assert_eq!(result, "abc");
+    }
+
+    #[test]
+    fn test_is_linux_function() {
+        let engine = TemplateEngine::new();
+        let result = engine
+            .render("{% if is_linux() %}yes{% else %}no{% endif %}")
+            .unwrap();
+
+        if std::env::consts::OS == "linux" {
+            assert_eq!(result, "yes");
+        } else {
+            assert_eq!(result, "no");
+        }
+    }
+
+    #[test]
+    fn test_default_filter() {
+        let engine = TemplateEngine::new();
+        let result = engine
+            .render("{{ undefined_var | default('fallback') }}")
+            .unwrap();
+        assert_eq!(result, "fallback");
+    }
+
+    #[test]
+    fn test_path_functions() {
+        let engine = TemplateEngine::new();
+
+        let result = engine
+            .render("{{ path_filename('/foo/bar.txt') }}")
+            .unwrap();
+        assert_eq!(result, "bar.txt");
+
+        let result = engine
+            .render("{{ path_extension('/foo/bar.txt') }}")
+            .unwrap();
+        assert_eq!(result, "txt");
+
+        let result = engine.render("{{ path_parent('/foo/bar.txt') }}").unwrap();
+        assert_eq!(result, "/foo");
+    }
+
+    #[test]
+    fn test_hash_str() {
+        let engine = TemplateEngine::new();
+        let result = engine.render("{{ hash_str('hello') }}").unwrap();
+        // BLAKE3 hash of "hello"
+        assert_eq!(result.len(), 64); // 32 bytes = 64 hex chars
+    }
+
+    #[test]
+    fn test_from_json() {
+        let engine = TemplateEngine::new();
+        let template = r#"{% set data = from_json('{"name": "test", "count": 42}') %}{{ data.name }}-{{ data.count }}"#;
+        let result = engine.render(template).unwrap();
+        assert_eq!(result, "test-42");
+    }
+
+    #[test]
+    fn test_starts_ends_with() {
+        let engine = TemplateEngine::new();
+
+        let result = engine
+            .render("{% if starts_with('hello', 'he') %}yes{% endif %}")
+            .unwrap();
+        assert_eq!(result, "yes");
+
+        let result = engine
+            .render("{% if ends_with('hello', 'lo') %}yes{% endif %}")
+            .unwrap();
+        assert_eq!(result, "yes");
+    }
+}
diff --git a/crates/doot-core/src/encryption/mod.rs b/crates/doot-core/src/encryption/mod.rs
index 212b522..e491be3 100644
--- a/crates/doot-core/src/encryption/mod.rs
+++ b/crates/doot-core/src/encryption/mod.rs
@@ -91,10 +91,9 @@ impl AgeEncryption {
 
     /// Decrypts data using the configured identity.
     pub fn decrypt(&self, data: &[u8]) -> Result<Vec<u8>, EncryptionError> {
-        let identity = self
-            .identity
-            .as_ref()
-            .ok_or_else(|| EncryptionError::DecryptionFailed("no identity configured".to_string()))?;
+        let identity = self.identity.as_ref().ok_or_else(|| {
+            EncryptionError::DecryptionFailed("no identity configured".to_string())
+        })?;
 
         let decryptor = match age::Decryptor::new(data)
             .map_err(|e| EncryptionError::DecryptionFailed(e.to_string()))?
@@ -103,7 +102,7 @@ impl AgeEncryption {
             _ => {
                 return Err(EncryptionError::DecryptionFailed(
                     "unexpected decryptor type".to_string(),
-                ))
+                ));
             }
         };
 
diff --git a/crates/doot-core/src/lib.rs b/crates/doot-core/src/lib.rs
index bf84afe..f922854 100644
--- a/crates/doot-core/src/lib.rs
+++ b/crates/doot-core/src/lib.rs
@@ -12,7 +12,7 @@ pub mod package;
 pub mod state;
 
 pub use config::Config;
-pub use deploy::{Deployer, DeployResult};
+pub use deploy::{DeployResult, Deployer};
 pub use encryption::AgeEncryption;
 pub use hooks::HookRunner;
 pub use os::OsInfo;
diff --git a/crates/doot-core/src/os.rs b/crates/doot-core/src/os.rs
index cfcaf36..95c3bcb 100644
--- a/crates/doot-core/src/os.rs
+++ b/crates/doot-core/src/os.rs
@@ -135,7 +135,9 @@ fn command_exists(cmd: &str) -> bool {
     } else {
         // Fallback to hardcoded paths
         let paths = ["/usr/bin/", "/usr/local/bin/", "/bin/"];
-        paths.iter().any(|p| std::path::Path::new(&format!("{}{}", p, cmd)).exists())
+        paths
+            .iter()
+            .any(|p| std::path::Path::new(&format!("{}{}", p, cmd)).exists())
     };
 
     cache.insert(cmd.to_string(), exists);
diff --git a/crates/doot-core/src/package/apt.rs b/crates/doot-core/src/package/apt.rs
index a0dac36..17a2dcd 100644
--- a/crates/doot-core/src/package/apt.rs
+++ b/crates/doot-core/src/package/apt.rs
@@ -33,10 +33,7 @@ impl Apt {
         }
 
         let output = if self.use_sudo {
-            Command::new("sudo")
-                .arg("apt")
-                .args(args)
-                .output()?
+            Command::new("sudo").arg("apt").args(args).output()?
         } else {
             Command::new("apt").args(args).output()?
         };
@@ -136,9 +133,7 @@ impl PackageManager for Apt {
     }
 
     fn is_installed(&self, package: &str) -> Result<bool, PackageError> {
-        let output = Command::new("dpkg")
-            .args(["-s", package])
-            .output()?;
+        let output = Command::new("dpkg").args(["-s", package]).output()?;
 
         Ok(output.status.success())
     }
diff --git a/crates/doot-core/src/package/brew.rs b/crates/doot-core/src/package/brew.rs
index 187fc53..2bb3ec1 100644
--- a/crates/doot-core/src/package/brew.rs
+++ b/crates/doot-core/src/package/brew.rs
@@ -82,9 +82,7 @@ impl PackageManager for Brew {
     }
 
     fn is_installed(&self, package: &str) -> Result<bool, PackageError> {
-        let output = Command::new("brew")
-            .args(["list", package])
-            .output()?;
+        let output = Command::new("brew").args(["list", package]).output()?;
 
         Ok(output.status.success())
     }
diff --git a/crates/doot-core/src/package/mod.rs b/crates/doot-core/src/package/mod.rs
index 122200c..428d83f 100644
--- a/crates/doot-core/src/package/mod.rs
+++ b/crates/doot-core/src/package/mod.rs
@@ -62,7 +62,9 @@ pub trait PackageManager: Send + Sync {
 
 /// Returns true if running in test mode (DOOT_TEST_MODE=1)
 pub fn is_test_mode() -> bool {
-    std::env::var("DOOT_TEST_MODE").map(|v| v == "1").unwrap_or(false)
+    std::env::var("DOOT_TEST_MODE")
+        .map(|v| v == "1")
+        .unwrap_or(false)
 }
 
 /// Mock package manager for testing - doesn't actually install anything
diff --git a/crates/doot-core/src/package/pacman.rs b/crates/doot-core/src/package/pacman.rs
index 9691a82..8f283b0 100644
--- a/crates/doot-core/src/package/pacman.rs
+++ b/crates/doot-core/src/package/pacman.rs
@@ -33,10 +33,7 @@ impl Pacman {
         }
 
         let output = if self.use_sudo {
-            Command::new("sudo")
-                .arg("pacman")
-                .args(args)
-                .output()?
+            Command::new("sudo").arg("pacman").args(args).output()?
         } else {
             Command::new("pacman").args(args).output()?
         };
@@ -136,9 +133,7 @@ impl PackageManager for Pacman {
     }
 
     fn is_installed(&self, package: &str) -> Result<bool, PackageError> {
-        let output = Command::new("pacman")
-            .args(["-Q", package])
-            .output()?;
+        let output = Command::new("pacman").args(["-Q", package]).output()?;
 
         Ok(output.status.success())
     }
diff --git a/crates/doot-core/src/package/yay.rs b/crates/doot-core/src/package/yay.rs
index 0aa00df..74578be 100644
--- a/crates/doot-core/src/package/yay.rs
+++ b/crates/doot-core/src/package/yay.rs
@@ -84,9 +84,7 @@ impl PackageManager for Yay {
     }
 
     fn is_installed(&self, package: &str) -> Result<bool, PackageError> {
-        let output = Command::new("yay")
-            .args(["-Q", package])
-            .output()?;
+        let output = Command::new("yay").args(["-Q", package]).output()?;
 
         Ok(output.status.success())
     }
diff --git a/crates/doot-core/src/state/snapshot.rs b/crates/doot-core/src/state/snapshot.rs
index a91510b..db58651 100644
--- a/crates/doot-core/src/state/snapshot.rs
+++ b/crates/doot-core/src/state/snapshot.rs
@@ -56,11 +56,10 @@ impl Snapshot {
         for entry in std::fs::read_dir(snapshot_dir)? {
             let entry = entry?;
             let path = entry.path();
-            if path.extension().map(|e| e == "json").unwrap_or(false) {
-                if let Some(name) = path.file_stem() {
+            if path.extension().map(|e| e == "json").unwrap_or(false)
+                && let Some(name) = path.file_stem() {
                     snapshots.push(name.to_string_lossy().to_string());
                 }
-            }
         }
 
         snapshots.sort();
diff --git a/crates/doot-core/src/state/store.rs b/crates/doot-core/src/state/store.rs
index 7fa9ae9..e7e3662 100644
--- a/crates/doot-core/src/state/store.rs
+++ b/crates/doot-core/src/state/store.rs
@@ -41,6 +41,9 @@ pub struct DeploymentRecord {
     pub target_hash: String,
     pub deployed_at: String,
     pub mode: DeployMode,
+    /// Whether this file was deployed as a template (source != target content).
+    #[serde(default)]
+    pub template: bool,
 }
 
 /// Sync status after comparing current hashes with recorded state.
@@ -91,6 +94,17 @@ impl StateStore {
 
     /// Records a deployment with both source and target hashes.
     pub fn record_deployment(&mut self, source: &Path, target: &Path, mode: DeployMode) {
+        self.record_deployment_with_template(source, target, mode, false);
+    }
+
+    /// Records a deployment with template flag.
+    pub fn record_deployment_with_template(
+        &mut self,
+        source: &Path,
+        target: &Path,
+        mode: DeployMode,
+        template: bool,
+    ) {
         let source_hash = hash_path(source);
         let target_hash = hash_path(target);
 
@@ -101,6 +115,7 @@ impl StateStore {
             target_hash,
             deployed_at: chrono_now(),
             mode,
+            template,
         };
 
         self.state
@@ -111,10 +126,43 @@ impl StateStore {
 
     /// Checks sync status by comparing current hashes with recorded state.
     pub fn check_sync_status(&self, source: &Path, target: &Path) -> SyncStatus {
+        self.check_sync_status_with_config(source, target, None, None)
+    }
+
+    /// Checks sync status, also detecting if template flag changed in config.
+    pub fn check_sync_status_with_template(
+        &self,
+        source: &Path,
+        target: &Path,
+        current_template: Option<bool>,
+    ) -> SyncStatus {
+        self.check_sync_status_with_config(source, target, current_template, None)
+    }
+
+    /// Checks sync status, also detecting if config flags changed.
+    pub fn check_sync_status_with_config(
+        &self,
+        source: &Path,
+        target: &Path,
+        current_template: Option<bool>,
+        current_mode: Option<DeployMode>,
+    ) -> SyncStatus {
         let Some(record) = self.get_deployment(target) else {
             return SyncStatus::NotDeployed;
         };
 
+        // If template flag changed in config, force re-deploy
+        if let Some(is_template) = current_template
+            && is_template != record.template {
+                return SyncStatus::SourceChanged;
+            }
+
+        // If deploy mode changed in config, force re-deploy
+        if let Some(mode) = current_mode
+            && mode != record.mode {
+                return SyncStatus::SourceChanged;
+            }
+
         if !source.exists() {
             return SyncStatus::SourceMissing;
         }
@@ -124,6 +172,11 @@ impl StateStore {
 
         // If stored hashes are empty (legacy record), treat as needing re-sync
         if record.source_hash.is_empty() || record.target_hash.is_empty() {
+            // For templates, we can't compare source to target directly
+            if record.template {
+                return SyncStatus::SourceChanged;
+            }
+
             let current_source_hash = hash_path(source);
             let current_target_hash = hash_path(target);
 
diff --git a/crates/doot-lang/src/ast.rs b/crates/doot-lang/src/ast.rs
index 641b640..39b4691 100644
--- a/crates/doot-lang/src/ast.rs
+++ b/crates/doot-lang/src/ast.rs
@@ -36,7 +36,7 @@ pub enum Statement {
     TypeAlias(TypeAlias),
     Import(Import),
     Dotfile(Dotfile),
-    Package(Package),
+    Package(Box<Package>),
     Secret(Secret),
     Hook(Hook),
     MacroDecl(MacroDecl),
diff --git a/crates/doot-lang/src/builtins/async_ops.rs b/crates/doot-lang/src/builtins/async_ops.rs
index a5a4c1b..f34e1e4 100644
--- a/crates/doot-lang/src/builtins/async_ops.rs
+++ b/crates/doot-lang/src/builtins/async_ops.rs
@@ -11,7 +11,11 @@ pub fn race(args: &[Value]) -> Result<Value, EvalError> {
 pub fn fetch(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("fetch expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "fetch expects a URL string".to_string(),
+            ));
+        }
     };
 
     smol::block_on(async {
@@ -31,7 +35,11 @@ pub fn fetch(args: &[Value]) -> Result<Value, EvalError> {
 pub fn fetch_json(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("fetch_json expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "fetch_json expects a URL string".to_string(),
+            ));
+        }
     };
 
     smol::block_on(async {
@@ -51,7 +59,11 @@ pub fn fetch_json(args: &[Value]) -> Result<Value, EvalError> {
 pub fn fetch_bytes(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("fetch_bytes expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "fetch_bytes expects a URL string".to_string(),
+            ));
+        }
     };
 
     smol::block_on(async {
@@ -72,7 +84,11 @@ pub fn fetch_bytes(args: &[Value]) -> Result<Value, EvalError> {
 pub fn post(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("post expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "post expects a URL string".to_string(),
+            ));
+        }
     };
 
     let body = match args.get(1) {
@@ -98,7 +114,11 @@ pub fn post(args: &[Value]) -> Result<Value, EvalError> {
 pub fn post_json(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("post_json expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "post_json expects a URL string".to_string(),
+            ));
+        }
     };
 
     let data = args.get(1).unwrap_or(&Value::None);
@@ -123,13 +143,21 @@ pub fn post_json(args: &[Value]) -> Result<Value, EvalError> {
 pub fn download(args: &[Value]) -> Result<Value, EvalError> {
     let url = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("download expects a URL string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "download expects a URL string".to_string(),
+            ));
+        }
     };
 
     let path = match args.get(1) {
         Some(Value::Path(p)) => p.clone(),
         Some(Value::Str(s)) => std::path::PathBuf::from(s),
-        _ => return Err(EvalError::TypeError("download requires destination path".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "download requires destination path".to_string(),
+            ));
+        }
     };
 
     smol::block_on(async {
@@ -161,9 +189,7 @@ fn json_to_value(json: &serde_json::Value) -> Value {
             }
         }
         serde_json::Value::String(s) => Value::Str(s.clone()),
-        serde_json::Value::Array(arr) => {
-            Value::List(arr.iter().map(json_to_value).collect())
-        }
+        serde_json::Value::Array(arr) => Value::List(arr.iter().map(json_to_value).collect()),
         serde_json::Value::Object(obj) => {
             let fields: indexmap::IndexMap<String, Value> = obj
                 .iter()
@@ -183,9 +209,7 @@ fn value_to_json(val: &Value) -> serde_json::Value {
         Value::Str(s) => serde_json::Value::String(s.clone()),
         Value::Bool(b) => serde_json::Value::Bool(*b),
         Value::Path(p) => serde_json::Value::String(p.display().to_string()),
-        Value::List(items) => {
-            serde_json::Value::Array(items.iter().map(value_to_json).collect())
-        }
+        Value::List(items) => serde_json::Value::Array(items.iter().map(value_to_json).collect()),
         Value::Struct(_, fields) => {
             let map: serde_json::Map<String, serde_json::Value> = fields
                 .iter()
diff --git a/crates/doot-lang/src/builtins/collections.rs b/crates/doot-lang/src/builtins/collections.rs
index a7c1a5f..0c6fc7d 100644
--- a/crates/doot-lang/src/builtins/collections.rs
+++ b/crates/doot-lang/src/builtins/collections.rs
@@ -4,8 +4,17 @@ use crate::evaluator::{EvalError, Evaluator, Value};
 pub fn map(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<Value, EvalError> {
     let list = match args.first() {
         Some(Value::List(items)) => items.clone(),
-        Some(v) => return Err(EvalError::TypeError(format!("map expects list, got {}", v.type_name()))),
-        None => return Err(EvalError::TypeError("map requires a list argument".to_string())),
+        Some(v) => {
+            return Err(EvalError::TypeError(format!(
+                "map expects list, got {}",
+                v.type_name()
+            )));
+        }
+        None => {
+            return Err(EvalError::TypeError(
+                "map requires a list argument".to_string(),
+            ));
+        }
     };
 
     match args.get(1) {
@@ -34,11 +43,24 @@ pub fn map(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<
     }
 }
 
-pub fn filter(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<Value, EvalError> {
+pub fn filter(
+    eval: &mut Evaluator,
+    args: &[Value],
+    _arg_exprs: &[Expr],
+) -> Result<Value, EvalError> {
     let list = match args.first() {
         Some(Value::List(items)) => items.clone(),
-        Some(v) => return Err(EvalError::TypeError(format!("filter expects list, got {}", v.type_name()))),
-        None => return Err(EvalError::TypeError("filter requires a list argument".to_string())),
+        Some(v) => {
+            return Err(EvalError::TypeError(format!(
+                "filter expects list, got {}",
+                v.type_name()
+            )));
+        }
+        None => {
+            return Err(EvalError::TypeError(
+                "filter requires a list argument".to_string(),
+            ));
+        }
     };
 
     match args.get(1) {
@@ -60,22 +82,33 @@ pub fn filter(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Resu
         Some(Value::Function(func, func_env)) => {
             let mut results = Vec::new();
             for item in list {
-                let result = eval.call_fn(func, func_env, &[item.clone()])?;
+                let result = eval.call_fn(func, func_env, std::slice::from_ref(&item))?;
                 if result.is_truthy() {
                     results.push(item);
                 }
             }
             Ok(Value::List(results))
         }
-        _ => Err(EvalError::TypeError("filter requires a function".to_string())),
+        _ => Err(EvalError::TypeError(
+            "filter requires a function".to_string(),
+        )),
     }
 }
 
 pub fn fold(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<Value, EvalError> {
     let list = match args.first() {
         Some(Value::List(items)) => items.clone(),
-        Some(v) => return Err(EvalError::TypeError(format!("fold expects list, got {}", v.type_name()))),
-        None => return Err(EvalError::TypeError("fold requires a list argument".to_string())),
+        Some(v) => {
+            return Err(EvalError::TypeError(format!(
+                "fold expects list, got {}",
+                v.type_name()
+            )));
+        }
+        None => {
+            return Err(EvalError::TypeError(
+                "fold requires a list argument".to_string(),
+            ));
+        }
     };
 
     let init = args.get(1).cloned().unwrap_or(Value::None);
@@ -136,13 +169,18 @@ pub fn concat(args: &[Value]) -> Result<Value, EvalError> {
 
 pub fn zip(args: &[Value]) -> Result<Value, EvalError> {
     if args.len() < 2 {
-        return Err(EvalError::TypeError("zip requires at least 2 lists".to_string()));
+        return Err(EvalError::TypeError(
+            "zip requires at least 2 lists".to_string(),
+        ));
     }
 
-    let lists: Result<Vec<&Vec<Value>>, _> = args.iter().map(|a| match a {
-        Value::List(items) => Ok(items),
-        _ => Err(EvalError::TypeError("zip expects lists".to_string())),
-    }).collect();
+    let lists: Result<Vec<&Vec<Value>>, _> = args
+        .iter()
+        .map(|a| match a {
+            Value::List(items) => Ok(items),
+            _ => Err(EvalError::TypeError("zip expects lists".to_string())),
+        })
+        .collect();
     let lists = lists?;
 
     let min_len = lists.iter().map(|l| l.len()).min().unwrap_or(0);
@@ -189,7 +227,9 @@ pub fn len(args: &[Value]) -> Result<Value, EvalError> {
     match args.first() {
         Some(Value::List(items)) => Ok(Value::Int(items.len() as i64)),
         Some(Value::Str(s)) => Ok(Value::Int(s.len() as i64)),
-        _ => Err(EvalError::TypeError("len expects a list or string".to_string())),
+        _ => Err(EvalError::TypeError(
+            "len expects a list or string".to_string(),
+        )),
     }
 }
 
@@ -245,7 +285,11 @@ pub fn sort(args: &[Value]) -> Result<Value, EvalError> {
     Ok(Value::List(sortable.into_iter().map(|(v, _)| v).collect()))
 }
 
-pub fn sort_by(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<Value, EvalError> {
+pub fn sort_by(
+    eval: &mut Evaluator,
+    args: &[Value],
+    _arg_exprs: &[Expr],
+) -> Result<Value, EvalError> {
     let list = match args.first() {
         Some(Value::List(items)) => items.clone(),
         _ => return Err(EvalError::TypeError("sort_by expects a list".to_string())),
@@ -266,7 +310,9 @@ pub fn sort_by(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Res
             keyed.sort_by(|a, b| a.1.cmp(&b.1));
             Ok(Value::List(keyed.into_iter().map(|(v, _)| v).collect()))
         }
-        _ => Err(EvalError::TypeError("sort_by requires a function".to_string())),
+        _ => Err(EvalError::TypeError(
+            "sort_by requires a function".to_string(),
+        )),
     }
 }
 
@@ -305,7 +351,11 @@ pub fn seq(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<
     }
 }
 
-pub fn batch(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Result<Value, EvalError> {
+pub fn batch(
+    eval: &mut Evaluator,
+    args: &[Value],
+    _arg_exprs: &[Expr],
+) -> Result<Value, EvalError> {
     let list = match args.first() {
         Some(Value::List(items)) => items.clone(),
         _ => return Err(EvalError::TypeError("batch expects a list".to_string())),
@@ -313,7 +363,11 @@ pub fn batch(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Resul
 
     let batch_size = match args.get(1) {
         Some(Value::Int(n)) => *n as usize,
-        _ => return Err(EvalError::TypeError("batch requires batch size".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "batch requires batch size".to_string(),
+            ));
+        }
     };
 
     match args.get(2) {
@@ -332,7 +386,9 @@ pub fn batch(eval: &mut Evaluator, args: &[Value], _arg_exprs: &[Expr]) -> Resul
             }
             Ok(Value::List(results))
         }
-        _ => Err(EvalError::TypeError("batch requires a function".to_string())),
+        _ => Err(EvalError::TypeError(
+            "batch requires a function".to_string(),
+        )),
     }
 }
 
diff --git a/crates/doot-lang/src/builtins/crypto.rs b/crates/doot-lang/src/builtins/crypto.rs
index 9208adc..83a8aa5 100644
--- a/crates/doot-lang/src/builtins/crypto.rs
+++ b/crates/doot-lang/src/builtins/crypto.rs
@@ -16,7 +16,11 @@ pub fn hash_file(args: &[Value]) -> Result<Value, EvalError> {
 pub fn hash_str(args: &[Value]) -> Result<Value, EvalError> {
     let s = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("hash_str expects a string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "hash_str expects a string".to_string(),
+            ));
+        }
     };
 
     let hash = blake3::hash(s.as_bytes());
@@ -26,12 +30,20 @@ pub fn hash_str(args: &[Value]) -> Result<Value, EvalError> {
 pub fn encrypt_age(args: &[Value]) -> Result<Value, EvalError> {
     let content = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("encrypt_age expects content string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "encrypt_age expects content string".to_string(),
+            ));
+        }
     };
 
     let recipient = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("encrypt_age requires recipient public key".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "encrypt_age requires recipient public key".to_string(),
+            ));
+        }
     };
 
     let recipient = recipient
@@ -60,12 +72,20 @@ pub fn encrypt_age(args: &[Value]) -> Result<Value, EvalError> {
 pub fn decrypt_age(args: &[Value]) -> Result<Value, EvalError> {
     let encrypted = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("decrypt_age expects encrypted string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "decrypt_age expects encrypted string".to_string(),
+            ));
+        }
     };
 
     let identity_str = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("decrypt_age requires identity".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "decrypt_age requires identity".to_string(),
+            ));
+        }
     };
 
     let identity = identity_str
@@ -79,7 +99,11 @@ pub fn decrypt_age(args: &[Value]) -> Result<Value, EvalError> {
         .map_err(|e| EvalError::TypeError(format!("decryption error: {}", e)))?
     {
         age::Decryptor::Recipients(d) => d,
-        _ => return Err(EvalError::TypeError("unexpected decryptor type".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "unexpected decryptor type".to_string(),
+            ));
+        }
     };
 
     let mut decrypted = vec![];
@@ -92,10 +116,9 @@ pub fn decrypt_age(args: &[Value]) -> Result<Value, EvalError> {
         .read_to_end(&mut decrypted)
         .map_err(|e| EvalError::TypeError(format!("decryption error: {}", e)))?;
 
-    Ok(Value::Str(
-        String::from_utf8(decrypted)
-            .map_err(|e| EvalError::TypeError(format!("invalid UTF-8: {}", e)))?,
-    ))
+    Ok(Value::Str(String::from_utf8(decrypted).map_err(|e| {
+        EvalError::TypeError(format!("invalid UTF-8: {}", e))
+    })?))
 }
 
 fn base64_encode(data: &[u8]) -> String {
diff --git a/crates/doot-lang/src/builtins/io.rs b/crates/doot-lang/src/builtins/io.rs
index 84aeac0..52046ad 100644
--- a/crates/doot-lang/src/builtins/io.rs
+++ b/crates/doot-lang/src/builtins/io.rs
@@ -20,7 +20,11 @@ pub fn write_file(args: &[Value]) -> Result<Value, EvalError> {
     let path = get_path(args)?;
     let content = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("write_file requires content string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "write_file requires content string".to_string(),
+            ));
+        }
     };
     std::fs::write(&path, content)?;
     Ok(Value::Bool(true))
@@ -31,7 +35,11 @@ pub fn copy_file(args: &[Value]) -> Result<Value, EvalError> {
     let dst = match args.get(1) {
         Some(Value::Path(p)) => p.clone(),
         Some(Value::Str(s)) => expand_path(s),
-        _ => return Err(EvalError::TypeError("copy_file requires destination path".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "copy_file requires destination path".to_string(),
+            ));
+        }
     };
     std::fs::copy(&src, &dst)?;
     Ok(Value::Bool(true))
@@ -71,7 +79,11 @@ pub fn list_dir(args: &[Value]) -> Result<Value, EvalError> {
 pub fn glob_files(args: &[Value]) -> Result<Value, EvalError> {
     let pattern = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("glob expects a pattern string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "glob expects a pattern string".to_string(),
+            ));
+        }
     };
 
     let entries: Vec<Value> = glob::glob(pattern)
@@ -127,7 +139,11 @@ pub fn path_join(args: &[Value]) -> Result<Value, EvalError> {
         match arg {
             Value::Path(p) => result.push(p),
             Value::Str(s) => result.push(s),
-            _ => return Err(EvalError::TypeError("path_join expects paths or strings".to_string())),
+            _ => {
+                return Err(EvalError::TypeError(
+                    "path_join expects paths or strings".to_string(),
+                ));
+            }
         }
     }
     Ok(Value::Path(result))
@@ -135,7 +151,9 @@ pub fn path_join(args: &[Value]) -> Result<Value, EvalError> {
 
 pub fn path_parent(args: &[Value]) -> Result<Value, EvalError> {
     let path = get_path(args)?;
-    Ok(Value::Path(path.parent().map(|p| p.to_path_buf()).unwrap_or_default()))
+    Ok(Value::Path(
+        path.parent().map(|p| p.to_path_buf()).unwrap_or_default(),
+    ))
 }
 
 pub fn path_filename(args: &[Value]) -> Result<Value, EvalError> {
@@ -167,7 +185,11 @@ pub fn config_dir() -> Result<Value, EvalError> {
 pub fn config_path(args: &[Value]) -> Result<Value, EvalError> {
     let app = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("config_path expects an app name string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "config_path expects an app name string".to_string(),
+            ));
+        }
     };
     let config = dirs::config_dir().unwrap_or_default();
     Ok(Value::Path(config.join(app)))
@@ -184,27 +206,31 @@ pub fn cache_dir() -> Result<Value, EvalError> {
 pub fn exec(args: &[Value]) -> Result<Value, EvalError> {
     let cmd = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("exec expects a command string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "exec expects a command string".to_string(),
+            ));
+        }
     };
 
-    let output = Command::new("sh")
-        .arg("-c")
-        .arg(cmd)
-        .output()?;
+    let output = Command::new("sh").arg("-c").arg(cmd).output()?;
 
-    Ok(Value::Str(String::from_utf8_lossy(&output.stdout).to_string()))
+    Ok(Value::Str(
+        String::from_utf8_lossy(&output.stdout).to_string(),
+    ))
 }
 
 pub fn exec_with_status(args: &[Value]) -> Result<Value, EvalError> {
     let cmd = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("exec_with_status expects a command string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "exec_with_status expects a command string".to_string(),
+            ));
+        }
     };
 
-    let status = Command::new("sh")
-        .arg("-c")
-        .arg(cmd)
-        .status()?;
+    let status = Command::new("sh").arg("-c").arg(cmd).status()?;
 
     Ok(Value::Int(status.code().unwrap_or(-1) as i64))
 }
@@ -216,12 +242,14 @@ pub fn shell(args: &[Value]) -> Result<Value, EvalError> {
 pub fn which(args: &[Value]) -> Result<Value, EvalError> {
     let cmd = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("which expects a command name".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "which expects a command name".to_string(),
+            ));
+        }
     };
 
-    let output = Command::new("which")
-        .arg(cmd)
-        .output()?;
+    let output = Command::new("which").arg(cmd).output()?;
 
     if output.status.success() {
         let path = String::from_utf8_lossy(&output.stdout).trim().to_string();
@@ -240,7 +268,11 @@ pub fn to_json(args: &[Value]) -> Result<Value, EvalError> {
 pub fn from_json(args: &[Value]) -> Result<Value, EvalError> {
     let s = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("from_json expects a string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "from_json expects a string".to_string(),
+            ));
+        }
     };
 
     let json: serde_json::Value = serde_json::from_str(s)
@@ -260,11 +292,15 @@ pub fn to_toml(args: &[Value]) -> Result<Value, EvalError> {
 pub fn from_toml(args: &[Value]) -> Result<Value, EvalError> {
     let s = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("from_toml expects a string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "from_toml expects a string".to_string(),
+            ));
+        }
     };
 
-    let toml_val: toml::Value = toml::from_str(s)
-        .map_err(|e| EvalError::TypeError(format!("invalid TOML: {}", e)))?;
+    let toml_val: toml::Value =
+        toml::from_str(s).map_err(|e| EvalError::TypeError(format!("invalid TOML: {}", e)))?;
 
     Ok(toml_to_value(&toml_val))
 }
@@ -272,7 +308,9 @@ pub fn from_toml(args: &[Value]) -> Result<Value, EvalError> {
 pub fn to_yaml(args: &[Value]) -> Result<Value, EvalError> {
     let val = args.first().unwrap_or(&Value::None);
     let json = value_to_json(val);
-    Ok(Value::Str(serde_json::to_string_pretty(&json).unwrap_or_default()))
+    Ok(Value::Str(
+        serde_json::to_string_pretty(&json).unwrap_or_default(),
+    ))
 }
 
 pub fn from_yaml(args: &[Value]) -> Result<Value, EvalError> {
@@ -288,9 +326,9 @@ fn get_path(args: &[Value]) -> Result<PathBuf, EvalError> {
 }
 
 fn expand_path(s: &str) -> PathBuf {
-    if s.starts_with('~') {
+    if let Some(stripped) = s.strip_prefix('~') {
         let home = dirs::home_dir().unwrap_or_default();
-        home.join(s.strip_prefix("~/").unwrap_or(&s[1..]))
+        home.join(stripped.strip_prefix('/').unwrap_or(stripped))
     } else {
         PathBuf::from(s)
     }
@@ -314,9 +352,7 @@ fn value_to_json(val: &Value) -> serde_json::Value {
         Value::Str(s) => serde_json::Value::String(s.clone()),
         Value::Bool(b) => serde_json::Value::Bool(*b),
         Value::Path(p) => serde_json::Value::String(p.display().to_string()),
-        Value::List(items) => {
-            serde_json::Value::Array(items.iter().map(value_to_json).collect())
-        }
+        Value::List(items) => serde_json::Value::Array(items.iter().map(value_to_json).collect()),
         Value::Struct(_, fields) => {
             let map: serde_json::Map<String, serde_json::Value> = fields
                 .iter()
@@ -343,9 +379,7 @@ fn json_to_value(json: &serde_json::Value) -> Value {
             }
         }
         serde_json::Value::String(s) => Value::Str(s.clone()),
-        serde_json::Value::Array(arr) => {
-            Value::List(arr.iter().map(json_to_value).collect())
-        }
+        serde_json::Value::Array(arr) => Value::List(arr.iter().map(json_to_value).collect()),
         serde_json::Value::Object(obj) => {
             let fields: indexmap::IndexMap<String, Value> = obj
                 .iter()
@@ -363,9 +397,7 @@ fn value_to_toml(val: &Value) -> toml::Value {
         Value::Str(s) => toml::Value::String(s.clone()),
         Value::Bool(b) => toml::Value::Boolean(*b),
         Value::Path(p) => toml::Value::String(p.display().to_string()),
-        Value::List(items) => {
-            toml::Value::Array(items.iter().map(value_to_toml).collect())
-        }
+        Value::List(items) => toml::Value::Array(items.iter().map(value_to_toml).collect()),
         Value::Struct(_, fields) => {
             let map: toml::map::Map<String, toml::Value> = fields
                 .iter()
@@ -383,9 +415,7 @@ fn toml_to_value(toml: &toml::Value) -> Value {
         toml::Value::Integer(i) => Value::Int(*i),
         toml::Value::Float(f) => Value::Float(*f),
         toml::Value::String(s) => Value::Str(s.clone()),
-        toml::Value::Array(arr) => {
-            Value::List(arr.iter().map(toml_to_value).collect())
-        }
+        toml::Value::Array(arr) => Value::List(arr.iter().map(toml_to_value).collect()),
         toml::Value::Table(table) => {
             let fields: indexmap::IndexMap<String, Value> = table
                 .iter()
diff --git a/crates/doot-lang/src/builtins/mod.rs b/crates/doot-lang/src/builtins/mod.rs
index 7edca41..4ee4c0d 100644
--- a/crates/doot-lang/src/builtins/mod.rs
+++ b/crates/doot-lang/src/builtins/mod.rs
@@ -146,22 +146,31 @@ pub fn call_method(
                 }
             }
             "map" => {
-                let all_args = std::iter::once(obj.clone()).chain(args.iter().cloned()).collect::<Vec<_>>();
+                let all_args = std::iter::once(obj.clone())
+                    .chain(args.iter().cloned())
+                    .collect::<Vec<_>>();
                 collections::map(eval, &all_args, arg_exprs)
             }
             "filter" => {
-                let all_args = std::iter::once(obj.clone()).chain(args.iter().cloned()).collect::<Vec<_>>();
+                let all_args = std::iter::once(obj.clone())
+                    .chain(args.iter().cloned())
+                    .collect::<Vec<_>>();
                 collections::filter(eval, &all_args, arg_exprs)
             }
             "fold" => {
-                let all_args = std::iter::once(obj.clone()).chain(args.iter().cloned()).collect::<Vec<_>>();
+                let all_args = std::iter::once(obj.clone())
+                    .chain(args.iter().cloned())
+                    .collect::<Vec<_>>();
                 collections::fold(eval, &all_args, arg_exprs)
             }
             "join" => {
-                let sep = args.first().map(|v| match v {
-                    Value::Str(s) => s.as_str(),
-                    _ => "",
-                }).unwrap_or("");
+                let sep = args
+                    .first()
+                    .map(|v| match v {
+                        Value::Str(s) => s.as_str(),
+                        _ => "",
+                    })
+                    .unwrap_or("");
                 let result = items
                     .iter()
                     .map(|v| v.to_string_repr())
@@ -170,7 +179,9 @@ pub fn call_method(
                 Ok(Value::Str(result))
             }
             "sort" => {
-                let all_args = std::iter::once(obj.clone()).chain(args.iter().cloned()).collect::<Vec<_>>();
+                let all_args = std::iter::once(obj.clone())
+                    .chain(args.iter().cloned())
+                    .collect::<Vec<_>>();
                 collections::sort(&all_args)
             }
             "reverse" => {
@@ -179,7 +190,9 @@ pub fn call_method(
                 Ok(Value::List(reversed))
             }
             "unique" => {
-                let all_args = std::iter::once(obj.clone()).chain(args.iter().cloned()).collect::<Vec<_>>();
+                let all_args = std::iter::once(obj.clone())
+                    .chain(args.iter().cloned())
+                    .collect::<Vec<_>>();
                 collections::unique(&all_args)
             }
             _ => Err(EvalError::UndefinedFunction(format!("list.{}", method))),
@@ -191,19 +204,21 @@ pub fn call_method(
             "lower" => Ok(Value::Str(s.to_lowercase())),
             "trim" => Ok(Value::Str(s.trim().to_string())),
             "split" => {
-                let sep = args.first().map(|v| match v {
-                    Value::Str(s) => s.as_str(),
-                    _ => " ",
-                }).unwrap_or(" ");
+                let sep = args
+                    .first()
+                    .map(|v| match v {
+                        Value::Str(s) => s.as_str(),
+                        _ => " ",
+                    })
+                    .unwrap_or(" ");
                 let parts: Vec<Value> = s.split(sep).map(|p| Value::Str(p.to_string())).collect();
                 Ok(Value::List(parts))
             }
             "replace" => {
-                if args.len() >= 2 {
-                    if let (Value::Str(from), Value::Str(to)) = (&args[0], &args[1]) {
+                if args.len() >= 2
+                    && let (Value::Str(from), Value::Str(to)) = (&args[0], &args[1]) {
                         return Ok(Value::Str(s.replace(from, to)));
                     }
-                }
                 Ok(Value::Str(s.clone()))
             }
             "starts_with" => {
@@ -231,9 +246,19 @@ pub fn call_method(
         },
 
         Value::Path(p) => match method {
-            "parent" => Ok(Value::Path(p.parent().map(|p| p.to_path_buf()).unwrap_or_default())),
-            "filename" => Ok(Value::Str(p.file_name().map(|s| s.to_string_lossy().to_string()).unwrap_or_default())),
-            "extension" => Ok(Value::Str(p.extension().map(|s| s.to_string_lossy().to_string()).unwrap_or_default())),
+            "parent" => Ok(Value::Path(
+                p.parent().map(|p| p.to_path_buf()).unwrap_or_default(),
+            )),
+            "filename" => Ok(Value::Str(
+                p.file_name()
+                    .map(|s| s.to_string_lossy().to_string())
+                    .unwrap_or_default(),
+            )),
+            "extension" => Ok(Value::Str(
+                p.extension()
+                    .map(|s| s.to_string_lossy().to_string())
+                    .unwrap_or_default(),
+            )),
             "exists" => Ok(Value::Bool(p.exists())),
             "is_file" => Ok(Value::Bool(p.is_file())),
             "is_dir" => Ok(Value::Bool(p.is_dir())),
@@ -256,15 +281,14 @@ pub fn call_method(
                         let mut method_args = vec![obj.clone()];
                         method_args.extend(args.iter().cloned());
                         let env_clone = eval.env().clone();
-                        return eval.call_function(&m, &env_clone, &method_args);
+                        return eval.call_function(m, &env_clone, &method_args);
                     }
                 }
             }
-            if let Some(field) = fields.get(method) {
-                if let Value::Function(func, env) = field {
+            if let Some(field) = fields.get(method)
+                && let Value::Function(func, env) = field {
                     return eval.call_function(func, env, args);
                 }
-            }
             Err(EvalError::FieldNotFound {
                 ty: name.clone(),
                 field: method.to_string(),
@@ -295,7 +319,9 @@ fn options_unwrap(args: &[Value]) -> Result<Value, EvalError> {
     match args.first() {
         Some(Value::None) => Err(EvalError::TypeError("unwrap called on none".to_string())),
         Some(v) => Ok(v.clone()),
-        None => Err(EvalError::TypeError("unwrap requires an argument".to_string())),
+        None => Err(EvalError::TypeError(
+            "unwrap requires an argument".to_string(),
+        )),
     }
 }
 
@@ -308,18 +334,22 @@ fn options_unwrap_or(args: &[Value]) -> Result<Value, EvalError> {
 }
 
 fn options_is_some(args: &[Value]) -> Result<Value, EvalError> {
-    Ok(Value::Bool(!matches!(args.first(), Some(Value::None) | None)))
+    Ok(Value::Bool(!matches!(
+        args.first(),
+        Some(Value::None) | None
+    )))
 }
 
 fn options_is_none(args: &[Value]) -> Result<Value, EvalError> {
-    Ok(Value::Bool(matches!(args.first(), Some(Value::None) | None)))
+    Ok(Value::Bool(matches!(
+        args.first(),
+        Some(Value::None) | None
+    )))
 }
 
 fn env_get(args: &[Value]) -> Result<Value, EvalError> {
     if let Some(Value::Str(key)) = args.first() {
-        Ok(std::env::var(key)
-            .map(Value::Str)
-            .unwrap_or(Value::None))
+        Ok(std::env::var(key).map(Value::Str).unwrap_or(Value::None))
     } else {
         Ok(Value::None)
     }
diff --git a/crates/doot-lang/src/builtins/strings.rs b/crates/doot-lang/src/builtins/strings.rs
index 27f9641..787e734 100644
--- a/crates/doot-lang/src/builtins/strings.rs
+++ b/crates/doot-lang/src/builtins/strings.rs
@@ -64,12 +64,20 @@ pub fn replace(args: &[Value]) -> Result<Value, EvalError> {
 
     let from = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("replace requires from string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "replace requires from string".to_string(),
+            ));
+        }
     };
 
     let to = match args.get(2) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("replace requires to string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "replace requires to string".to_string(),
+            ));
+        }
     };
 
     Ok(Value::Str(s.replace(from.as_str(), to.as_str())))
@@ -78,12 +86,20 @@ pub fn replace(args: &[Value]) -> Result<Value, EvalError> {
 pub fn starts_with(args: &[Value]) -> Result<Value, EvalError> {
     let s = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("starts_with expects a string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "starts_with expects a string".to_string(),
+            ));
+        }
     };
 
     let prefix = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("starts_with requires prefix".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "starts_with requires prefix".to_string(),
+            ));
+        }
     };
 
     Ok(Value::Bool(s.starts_with(prefix.as_str())))
@@ -92,12 +108,20 @@ pub fn starts_with(args: &[Value]) -> Result<Value, EvalError> {
 pub fn ends_with(args: &[Value]) -> Result<Value, EvalError> {
     let s = match args.first() {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("ends_with expects a string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "ends_with expects a string".to_string(),
+            ));
+        }
     };
 
     let suffix = match args.get(1) {
         Some(Value::Str(s)) => s,
-        _ => return Err(EvalError::TypeError("ends_with requires suffix".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "ends_with requires suffix".to_string(),
+            ));
+        }
     };
 
     Ok(Value::Bool(s.ends_with(suffix.as_str())))
@@ -106,7 +130,11 @@ pub fn ends_with(args: &[Value]) -> Result<Value, EvalError> {
 pub fn format(args: &[Value]) -> Result<Value, EvalError> {
     let template = match args.first() {
         Some(Value::Str(s)) => s.clone(),
-        _ => return Err(EvalError::TypeError("format expects a template string".to_string())),
+        _ => {
+            return Err(EvalError::TypeError(
+                "format expects a template string".to_string(),
+            ));
+        }
     };
 
     let mut result = template;
diff --git a/crates/doot-lang/src/evaluator.rs b/crates/doot-lang/src/evaluator.rs
index 712e1e8..37f1261 100644
--- a/crates/doot-lang/src/evaluator.rs
+++ b/crates/doot-lang/src/evaluator.rs
@@ -128,7 +128,11 @@ impl Value {
             Value::Path(p) => p.display().to_string(),
             Value::List(items) => {
                 // Join list items with colon (PATH-style)
-                items.iter().map(|v| v.to_env_string()).collect::<Vec<_>>().join(":")
+                items
+                    .iter()
+                    .map(|v| v.to_env_string())
+                    .collect::<Vec<_>>()
+                    .join(":")
             }
             Value::None => String::new(),
             _ => self.to_string_repr(),
@@ -347,9 +351,18 @@ impl Evaluator {
             EnumDecl {
                 name: "Os".to_string(),
                 variants: vec![
-                    EnumVariant { name: "Linux".to_string(), fields: None },
-                    EnumVariant { name: "MacOS".to_string(), fields: None },
-                    EnumVariant { name: "Windows".to_string(), fields: None },
+                    EnumVariant {
+                        name: "Linux".to_string(),
+                        fields: None,
+                    },
+                    EnumVariant {
+                        name: "MacOS".to_string(),
+                        fields: None,
+                    },
+                    EnumVariant {
+                        name: "Windows".to_string(),
+                        fields: None,
+                    },
                 ],
             },
         );
@@ -365,7 +378,10 @@ impl Evaluator {
         };
         env.define("os".to_string(), os_val);
         env.define("distro".to_string(), Value::Str(sys.distro.clone()));
-        env.define("pkg_manager".to_string(), Value::Str(sys.pkg_manager.clone()));
+        env.define(
+            "pkg_manager".to_string(),
+            Value::Str(sys.pkg_manager.clone()),
+        );
         env.define("hostname".to_string(), Value::Str(sys.hostname.clone()));
         env.define("arch".to_string(), Value::Str(sys.arch.to_string()));
     }
@@ -383,13 +399,17 @@ impl Evaluator {
         let mut vars = self.env.get_all_variables();
 
         // Add doot global variables
-        vars.insert("DOOT_HOME".to_string(), Self::home_dir().display().to_string());
-        vars.insert("DOOT_CONFIG_DIR".to_string(),
+        vars.insert(
+            "DOOT_HOME".to_string(),
+            Self::home_dir().display().to_string(),
+        );
+        vars.insert(
+            "DOOT_CONFIG_DIR".to_string(),
             dirs::config_dir()
                 .unwrap_or_else(|| Self::home_dir().join(".config"))
                 .join("doot")
                 .display()
-                .to_string()
+                .to_string(),
         );
         vars.insert("DOOT_OS".to_string(), std::env::consts::OS.to_string());
         vars.insert("DOOT_ARCH".to_string(), std::env::consts::ARCH.to_string());
@@ -403,11 +423,10 @@ impl Evaluator {
                 let value = self.eval_expr(&decl.value)?;
 
                 // Handle special config variables
-                if decl.name == "sandbox" {
-                    if let Value::Bool(b) = &value {
+                if decl.name == "sandbox"
+                    && let Value::Bool(b) = &value {
                         self.result.sandbox = *b;
                     }
-                }
 
                 self.env.define(decl.name.clone(), value);
                 Ok(None)
@@ -718,12 +737,10 @@ impl Evaluator {
                     Value::Lambda(params, body, lambda_env) => {
                         self.call_lambda(&params, &body, &lambda_env, &arg_vals)
                     }
-                    _ => {
-                        Err(EvalError::TypeError(format!(
-                            "cannot call {}",
-                            callee_val.type_name()
-                        )))
-                    }
+                    _ => Err(EvalError::TypeError(format!(
+                        "cannot call {}",
+                        callee_val.type_name()
+                    ))),
                 }
             }
 
@@ -741,10 +758,13 @@ impl Evaluator {
                 let obj_val = self.eval_expr(obj)?;
                 match obj_val {
                     Value::Struct(name, fields) => {
-                        fields.get(field).cloned().ok_or_else(|| EvalError::FieldNotFound {
-                            ty: name,
-                            field: field.clone(),
-                        })
+                        fields
+                            .get(field)
+                            .cloned()
+                            .ok_or_else(|| EvalError::FieldNotFound {
+                                ty: name,
+                                field: field.clone(),
+                            })
                     }
                     _ => Err(EvalError::TypeError(format!(
                         "cannot access field on {}",
@@ -759,22 +779,17 @@ impl Evaluator {
 
                 match (obj_val, idx_val) {
                     (Value::List(items), Value::Int(i)) => {
-                        let index = if i < 0 {
-                            items.len() as i64 + i
-                        } else {
-                            i
-                        };
-                        items.get(index as usize).cloned().ok_or(EvalError::IndexOutOfBounds {
-                            index: i,
-                            len: items.len(),
-                        })
+                        let index = if i < 0 { items.len() as i64 + i } else { i };
+                        items
+                            .get(index as usize)
+                            .cloned()
+                            .ok_or(EvalError::IndexOutOfBounds {
+                                index: i,
+                                len: items.len(),
+                            })
                     }
                     (Value::Str(s), Value::Int(i)) => {
-                        let index = if i < 0 {
-                            s.len() as i64 + i
-                        } else {
-                            i
-                        };
+                        let index = if i < 0 { s.len() as i64 + i } else { i };
                         s.chars()
                             .nth(index as usize)
                             .map(|c| Value::Str(c.to_string()))
@@ -815,9 +830,7 @@ impl Evaluator {
                 Ok(Value::Struct(name.clone(), values))
             }
 
-            Expr::EnumVariant(ty, variant) => {
-                Ok(Value::Enum(ty.clone(), variant.clone()))
-            }
+            Expr::EnumVariant(ty, variant) => Ok(Value::Enum(ty.clone(), variant.clone())),
 
             Expr::If(cond, then_expr, else_expr) => {
                 let cond_val = self.eval_expr(cond)?;
@@ -830,13 +843,13 @@ impl Evaluator {
                 }
             }
 
-            Expr::Lambda(params, body, ..) => {
-                Ok(Value::Lambda(params.clone(), *body.clone(), self.env.clone()))
-            }
+            Expr::Lambda(params, body, ..) => Ok(Value::Lambda(
+                params.clone(),
+                *body.clone(),
+                self.env.clone(),
+            )),
 
-            Expr::Await(expr) => {
-                self.eval_expr(expr)
-            }
+            Expr::Await(expr) => self.eval_expr(expr),
 
             Expr::Path(left, right) => {
                 let left_path = self.eval_to_path(left)?;
@@ -1126,9 +1139,9 @@ impl Evaluator {
         match val {
             Value::Path(p) => Ok(p),
             Value::Str(s) => {
-                if s.starts_with('~') {
+                if let Some(stripped) = s.strip_prefix('~') {
                     let home = Self::home_dir();
-                    Ok(home.join(s.strip_prefix("~/").unwrap_or(&s[1..])))
+                    Ok(home.join(stripped.strip_prefix('/').unwrap_or(stripped)))
                 } else {
                     Ok(PathBuf::from(s))
                 }
@@ -1208,7 +1221,9 @@ fn command_exists(cmd: &str) -> bool {
     } else {
         // Fallback to hardcoded paths
         let paths = ["/usr/bin/", "/usr/local/bin/", "/bin/"];
-        paths.iter().any(|p| std::path::Path::new(&format!("{}{}", p, cmd)).exists())
+        paths
+            .iter()
+            .any(|p| std::path::Path::new(&format!("{}{}", p, cmd)).exists())
     };
 
     cache.insert(cmd.to_string(), exists);
diff --git a/crates/doot-lang/src/lexer.rs b/crates/doot-lang/src/lexer.rs
index 01b7ef7..9d6b6f1 100644
--- a/crates/doot-lang/src/lexer.rs
+++ b/crates/doot-lang/src/lexer.rs
@@ -198,17 +198,16 @@ impl Lexer {
             .ignore_then(text::digits(16))
             .map(|s: String| Token::Int(i64::from_str_radix(&s, 16).unwrap_or(0)));
 
-        let decimal = text::int(10)
-            .map(|s: String| Token::Int(s.parse().unwrap()));
+        let decimal = text::int(10).map(|s: String| Token::Int(s.parse().unwrap()));
 
         let int = octal.or(hex).or(decimal);
 
-        let float = text::int(10)
-            .then(just('.').then(text::digits(10)))
-            .map(|(a, (_, b)): (String, (char, String))| {
+        let float = text::int(10).then(just('.').then(text::digits(10))).map(
+            |(a, (_, b)): (String, (char, String))| {
                 let f: f64 = format!("{}.{}", a, b).parse().unwrap();
                 Token::Float(OrderedFloat(f))
-            });
+            },
+        );
 
         let escape = just('\\').ignore_then(
             just('\\')
@@ -226,14 +225,15 @@ impl Lexer {
             .map(Token::Str);
 
         // Heredoc: >>>...<<<
-        let heredoc = just(">>>")
-            .ignore_then(take_until(just("<<<")))
-            .map(|(chars, _): (Vec<char>, _)| {
-                let s: String = chars.into_iter().collect();
-                // Trim leading newline if present
-                let s = s.strip_prefix('\n').unwrap_or(&s);
-                Token::Str(s.to_string())
-            });
+        let heredoc =
+            just(">>>")
+                .ignore_then(take_until(just("<<<")))
+                .map(|(chars, _): (Vec<char>, _)| {
+                    let s: String = chars.into_iter().collect();
+                    // Trim leading newline if present
+                    let s = s.strip_prefix('\n').unwrap_or(&s);
+                    Token::Str(s.to_string())
+                });
 
         let keyword_or_ident = text::ident().map(|s: String| match s.as_str() {
             "let" => Token::Let,
@@ -307,9 +307,7 @@ impl Lexer {
             just('#').to(Token::Hash),
         ));
 
-        let comment = just('#')
-            .then(none_of("\n").repeated())
-            .ignored();
+        let comment = just('#').then(none_of("\n").repeated()).ignored();
 
         let whitespace = just(' ').or(just('\t')).repeated().at_least(1).ignored();
 
@@ -361,9 +359,14 @@ impl Lexer {
 
                     if current_indent > last_indent {
                         indent_stack.push(current_indent);
-                        result.push(Spanned::new(Token::Indent(current_indent), span_start..span_start));
+                        result.push(Spanned::new(
+                            Token::Indent(current_indent),
+                            span_start..span_start,
+                        ));
                     } else {
-                        while indent_stack.len() > 1 && current_indent < *indent_stack.last().unwrap() {
+                        while indent_stack.len() > 1
+                            && current_indent < *indent_stack.last().unwrap()
+                        {
                             indent_stack.pop();
                             result.push(Spanned::new(Token::Dedent, span_start..span_start));
                         }
diff --git a/crates/doot-lang/src/lib.rs b/crates/doot-lang/src/lib.rs
index dc9faa8..0aca0b9 100644
--- a/crates/doot-lang/src/lib.rs
+++ b/crates/doot-lang/src/lib.rs
@@ -17,6 +17,6 @@ pub use ast::*;
 pub use evaluator::Evaluator;
 pub use lexer::Lexer;
 pub use parser::Parser;
-pub use planner::{validate_dotfile_targets, DotfileConflict, DotfileValidation, DotfileWarning};
+pub use planner::{DotfileConflict, DotfileValidation, DotfileWarning, validate_dotfile_targets};
 pub use type_checker::TypeChecker;
 pub use types::Type;
diff --git a/crates/doot-lang/src/macros.rs b/crates/doot-lang/src/macros.rs
index 801a7b6..dbda61a 100644
--- a/crates/doot-lang/src/macros.rs
+++ b/crates/doot-lang/src/macros.rs
@@ -33,17 +33,18 @@ impl MacroExpander {
         let expanded: Vec<Spanned<Statement>> = decl
             .body
             .iter()
-            .map(|stmt| Spanned::new(self.substitute_statement(&stmt.node, &substitutions), stmt.span.clone()))
+            .map(|stmt| {
+                Spanned::new(
+                    self.substitute_statement(&stmt.node, &substitutions),
+                    stmt.span.clone(),
+                )
+            })
             .collect();
 
         Some(expanded)
     }
 
-    fn substitute_statement(
-        &self,
-        stmt: &Statement,
-        subs: &HashMap<String, &Expr>,
-    ) -> Statement {
+    fn substitute_statement(&self, stmt: &Statement, subs: &HashMap<String, &Expr>) -> Statement {
         match stmt {
             Statement::VarDecl(decl) => Statement::VarDecl(VarDecl {
                 name: decl.name.clone(),
@@ -63,7 +64,7 @@ impl MacroExpander {
                 copy_patterns: dotfile.copy_patterns.clone(),
             }),
 
-            Statement::Package(pkg) => Statement::Package(Package {
+            Statement::Package(pkg) => Statement::Package(Box::new(Package {
                 default: pkg.default.as_ref().map(|e| self.substitute_expr(e, subs)),
                 brew: pkg.brew.as_ref().map(|s| PackageSpec {
                     name: self.substitute_expr(&s.name, subs),
@@ -86,7 +87,7 @@ impl MacroExpander {
                     tap: s.tap.clone(),
                 }),
                 when: pkg.when.as_ref().map(|e| self.substitute_expr(e, subs)),
-            }),
+            })),
 
             Statement::ForLoop(for_loop) => Statement::ForLoop(ForLoop {
                 var: for_loop.var.clone(),
@@ -94,9 +95,7 @@ impl MacroExpander {
                 body: for_loop
                     .body
                     .iter()
-                    .map(|s| {
-                        Spanned::new(self.substitute_statement(&s.node, subs), s.span.clone())
-                    })
+                    .map(|s| Spanned::new(self.substitute_statement(&s.node, subs), s.span.clone()))
                     .collect(),
             }),
 
@@ -105,9 +104,7 @@ impl MacroExpander {
                 then_body: if_stmt
                     .then_body
                     .iter()
-                    .map(|s| {
-                        Spanned::new(self.substitute_statement(&s.node, subs), s.span.clone())
-                    })
+                    .map(|s| Spanned::new(self.substitute_statement(&s.node, subs), s.span.clone()))
                     .collect(),
                 else_body: if_stmt.else_body.as_ref().map(|body| {
                     body.iter()
@@ -164,9 +161,12 @@ impl MacroExpander {
                 Box::new(self.substitute_expr(idx, subs)),
             ),
 
-            Expr::List(items) => {
-                Expr::List(items.iter().map(|i| self.substitute_expr(i, subs)).collect())
-            }
+            Expr::List(items) => Expr::List(
+                items
+                    .iter()
+                    .map(|i| self.substitute_expr(i, subs))
+                    .collect(),
+            ),
 
             Expr::StructInit(name, fields) => Expr::StructInit(
                 name.clone(),
@@ -184,23 +184,18 @@ impl MacroExpander {
                     .map(|e| Box::new(self.substitute_expr(e, subs))),
             ),
 
-            Expr::Lambda(params, body) => Expr::Lambda(
-                params.clone(),
-                Box::new(self.substitute_expr(body, subs)),
-            ),
-
-            Expr::Await(inner) => {
-                Expr::Await(Box::new(self.substitute_expr(inner, subs)))
+            Expr::Lambda(params, body) => {
+                Expr::Lambda(params.clone(), Box::new(self.substitute_expr(body, subs)))
             }
 
+            Expr::Await(inner) => Expr::Await(Box::new(self.substitute_expr(inner, subs))),
+
             Expr::Path(left, right) => Expr::Path(
                 Box::new(self.substitute_expr(left, subs)),
                 Box::new(self.substitute_expr(right, subs)),
             ),
 
-            Expr::HomePath(path) => {
-                Expr::HomePath(Box::new(self.substitute_expr(path, subs)))
-            }
+            Expr::HomePath(path) => Expr::HomePath(Box::new(self.substitute_expr(path, subs))),
 
             Expr::Interpolated(parts) => Expr::Interpolated(
                 parts
diff --git a/crates/doot-lang/src/parser.rs b/crates/doot-lang/src/parser.rs
index 6215e02..81f8d9e 100644
--- a/crates/doot-lang/src/parser.rs
+++ b/crates/doot-lang/src/parser.rs
@@ -2,8 +2,8 @@
 
 use crate::ast::*;
 use crate::lexer::Token;
-use chumsky::prelude::*;
 use chumsky::Parser as _;
+use chumsky::prelude::*;
 use std::collections::HashMap;
 
 /// Parses tokens into an AST.
@@ -33,10 +33,7 @@ impl Parser {
     fn statement_parser() -> impl chumsky::Parser<Token, Spanned<Statement>, Error = Simple<Token>>
     {
         recursive(|stmt| {
-            let whitespace = choice((
-                just(Token::Newline),
-                just(Token::Dedent),
-            )).repeated();
+            let whitespace = just(Token::Newline).repeated();
 
             let var_decl = Self::var_decl_parser().map(Statement::VarDecl);
             let fn_decl = Self::fn_decl_parser(stmt.clone()).map(Statement::FnDecl);
@@ -45,7 +42,7 @@ impl Parser {
             let type_alias = Self::type_alias_parser().map(Statement::TypeAlias);
             let import = Self::import_parser().map(Statement::Import);
             let dotfile = Self::dotfile_parser().map(Statement::Dotfile);
-            let package = Self::package_parser().map(Statement::Package);
+            let package = Self::package_parser().map(|p| Statement::Package(Box::new(p)));
             let secret = Self::secret_parser().map(Statement::Secret);
             let hook = Self::hook_parser().map(Statement::Hook);
             let simple_hook = Self::simple_hook_parser().map(Statement::Hook);
@@ -127,11 +124,7 @@ impl Parser {
         let param = Self::ident_parser()
             .then_ignore(just(Token::Colon))
             .then(Self::type_annotation_parser())
-            .then(
-                just(Token::Eq)
-                    .ignore_then(Self::expr_parser())
-                    .or_not(),
-            )
+            .then(just(Token::Eq).ignore_then(Self::expr_parser()).or_not())
             .map(|((name, ty), default)| FnParam { name, ty, default });
 
         param
@@ -146,11 +139,7 @@ impl Parser {
         let field = Self::ident_parser()
             .then_ignore(just(Token::Colon))
             .then(Self::type_annotation_parser())
-            .then(
-                just(Token::Eq)
-                    .ignore_then(Self::expr_parser())
-                    .or_not(),
-            )
+            .then(just(Token::Eq).ignore_then(Self::expr_parser()).or_not())
             .map(|((name, ty), default)| StructField { name, ty, default });
 
         let method = Self::fn_decl_parser(stmt);
@@ -161,12 +150,9 @@ impl Parser {
             .then_ignore(just(Token::Newline).repeated())
             .then_ignore(just(Token::Indent(0)).rewind().or_not())
             .then(
-                choice((
-                    field.map(Either::Left),
-                    method.map(Either::Right),
-                ))
-                .padded_by(just(Token::Newline).repeated())
-                .repeated(),
+                choice((field.map(Either::Left), method.map(Either::Right)))
+                    .padded_by(just(Token::Newline).repeated())
+                    .repeated(),
             )
             .then_ignore(just(Token::Dedent).or_not())
             .map(|(name, members)| {
@@ -178,7 +164,11 @@ impl Parser {
                         Either::Right(m) => methods.push(m),
                     }
                 }
-                StructDecl { name, fields, methods }
+                StructDecl {
+                    name,
+                    fields,
+                    methods,
+                }
             })
     }
 
@@ -339,10 +329,34 @@ impl Parser {
                 for (name, value) in fields {
                     match name.as_str() {
                         "default" => pkg.default = Some(value),
-                        "brew" => pkg.brew = Some(PackageSpec { name: value, cask: None, tap: None }),
-                        "apt" => pkg.apt = Some(PackageSpec { name: value, cask: None, tap: None }),
-                        "pacman" => pkg.pacman = Some(PackageSpec { name: value, cask: None, tap: None }),
-                        "yay" => pkg.yay = Some(PackageSpec { name: value, cask: None, tap: None }),
+                        "brew" => {
+                            pkg.brew = Some(PackageSpec {
+                                name: value,
+                                cask: None,
+                                tap: None,
+                            })
+                        }
+                        "apt" => {
+                            pkg.apt = Some(PackageSpec {
+                                name: value,
+                                cask: None,
+                                tap: None,
+                            })
+                        }
+                        "pacman" => {
+                            pkg.pacman = Some(PackageSpec {
+                                name: value,
+                                cask: None,
+                                tap: None,
+                            })
+                        }
+                        "yay" => {
+                            pkg.yay = Some(PackageSpec {
+                                name: value,
+                                cask: None,
+                                tap: None,
+                            })
+                        }
                         "when" => pkg.when = Some(value),
                         _ => {}
                     }
@@ -563,8 +577,8 @@ impl Parser {
             .then_ignore(just(Token::Dedent).or_not())
     }
 
-    fn type_annotation_parser(
-    ) -> impl chumsky::Parser<Token, TypeAnnotation, Error = Simple<Token>> {
+    fn type_annotation_parser() -> impl chumsky::Parser<Token, TypeAnnotation, Error = Simple<Token>>
+    {
         recursive(|ty| {
             let simple = Self::ident_parser().map(TypeAnnotation::Simple);
 
@@ -590,11 +604,7 @@ impl Parser {
 
             optional
                 .clone()
-                .then(
-                    just(Token::Pipe)
-                        .ignore_then(optional.clone())
-                        .repeated(),
-                )
+                .then(just(Token::Pipe).ignore_then(optional.clone()).repeated())
                 .map(|(first, rest)| {
                     if rest.is_empty() {
                         first
@@ -707,40 +717,44 @@ impl Parser {
                 paren,
             ));
 
-            let call_or_access = atom.then(
-                choice((
-                    expr.clone()
-                        .separated_by(just(Token::Comma))
-                        .allow_trailing()
-                        .delimited_by(just(Token::LParen), just(Token::RParen))
-                        .map(CallOrAccess::Call),
-                    just(Token::Dot)
-                        .ignore_then(Self::ident_parser())
-                        .then(
-                            expr.clone()
-                                .separated_by(just(Token::Comma))
-                                .allow_trailing()
-                                .delimited_by(just(Token::LParen), just(Token::RParen))
-                                .or_not(),
-                        )
-                        .map(|(name, args)| {
-                            if let Some(args) = args {
-                                CallOrAccess::MethodCall(name, args)
-                            } else {
-                                CallOrAccess::Field(name)
-                            }
-                        }),
-                    expr.clone()
-                        .delimited_by(just(Token::LBracket), just(Token::RBracket))
-                        .map(CallOrAccess::Index),
-                ))
-                .repeated(),
-            ).foldl(|e, access| match access {
-                CallOrAccess::Call(args) => Expr::Call(Box::new(e), args),
-                CallOrAccess::MethodCall(name, args) => Expr::MethodCall(Box::new(e), name, args),
-                CallOrAccess::Field(name) => Expr::Field(Box::new(e), name),
-                CallOrAccess::Index(idx) => Expr::Index(Box::new(e), Box::new(idx)),
-            });
+            let call_or_access = atom
+                .then(
+                    choice((
+                        expr.clone()
+                            .separated_by(just(Token::Comma))
+                            .allow_trailing()
+                            .delimited_by(just(Token::LParen), just(Token::RParen))
+                            .map(CallOrAccess::Call),
+                        just(Token::Dot)
+                            .ignore_then(Self::ident_parser())
+                            .then(
+                                expr.clone()
+                                    .separated_by(just(Token::Comma))
+                                    .allow_trailing()
+                                    .delimited_by(just(Token::LParen), just(Token::RParen))
+                                    .or_not(),
+                            )
+                            .map(|(name, args)| {
+                                if let Some(args) = args {
+                                    CallOrAccess::MethodCall(name, args)
+                                } else {
+                                    CallOrAccess::Field(name)
+                                }
+                            }),
+                        expr.clone()
+                            .delimited_by(just(Token::LBracket), just(Token::RBracket))
+                            .map(CallOrAccess::Index),
+                    ))
+                    .repeated(),
+                )
+                .foldl(|e, access| match access {
+                    CallOrAccess::Call(args) => Expr::Call(Box::new(e), args),
+                    CallOrAccess::MethodCall(name, args) => {
+                        Expr::MethodCall(Box::new(e), name, args)
+                    }
+                    CallOrAccess::Field(name) => Expr::Field(Box::new(e), name),
+                    CallOrAccess::Index(idx) => Expr::Index(Box::new(e), Box::new(idx)),
+                });
 
             let unary_ops = choice((
                 just(Token::Minus).to(UnaryOp::Neg),
@@ -752,7 +766,9 @@ impl Parser {
             let unary = unary_ops
                 .then(call_or_access)
                 .map(|(ops, expr)| {
-                    ops.into_iter().rev().fold(expr, |e, op| Expr::Unary(op, Box::new(e)))
+                    ops.into_iter()
+                        .rev()
+                        .fold(expr, |e, op| Expr::Unary(op, Box::new(e)))
                 })
                 .boxed();
 
@@ -819,7 +835,11 @@ impl Parser {
 
             or_expr
                 .clone()
-                .then(just(Token::QuestionQuestion).ignore_then(or_expr.clone()).repeated())
+                .then(
+                    just(Token::QuestionQuestion)
+                        .ignore_then(or_expr.clone())
+                        .repeated(),
+                )
                 .foldl(|a, b| Expr::Binary(Box::new(a), BinOp::NullCoalesce, Box::new(b)))
         })
     }
@@ -867,11 +887,10 @@ impl Parser {
             parts.push(InterpolatedPart::Literal(current));
         }
 
-        if parts.len() == 1 {
-            if let InterpolatedPart::Literal(s) = &parts[0] {
+        if parts.len() == 1
+            && let InterpolatedPart::Literal(s) = &parts[0] {
                 return Expr::Literal(Literal::Str(s.clone()));
             }
-        }
 
         Expr::Interpolated(parts)
     }
@@ -933,9 +952,7 @@ fn expr_to_permission_rules(expr: &Expr) -> Vec<PermissionRule> {
                         }
                     }
                     // Single mode in array (less common but supported)
-                    Expr::Literal(Literal::Int(mode)) => {
-                        Some(PermissionRule::Single(*mode as u32))
-                    }
+                    Expr::Literal(Literal::Int(mode)) => Some(PermissionRule::Single(*mode as u32)),
                     _ => None,
                 }
             })
diff --git a/crates/doot-lang/src/planner/executor.rs b/crates/doot-lang/src/planner/executor.rs
index d407269..f199f31 100644
--- a/crates/doot-lang/src/planner/executor.rs
+++ b/crates/doot-lang/src/planner/executor.rs
@@ -32,11 +32,7 @@ pub trait TaskHandler: Send + Sync {
     fn handle_package(&self, name: &str, manager: &str) -> TaskResult;
 
     /// Handles secret decryption.
-    fn handle_secret(
-        &self,
-        source: &std::path::Path,
-        target: &std::path::Path,
-    ) -> TaskResult;
+    fn handle_secret(&self, source: &std::path::Path, target: &std::path::Path) -> TaskResult;
 
     /// Handles hook execution.
     fn handle_hook(&self, command: &str) -> TaskResult;
@@ -90,13 +86,13 @@ impl<H: TaskHandler + 'static> Executor<H> {
 
     /// Executes tasks in parallel batches.
     pub fn execute_parallel(&self) -> Result<ExecutionReport, ExecutionError> {
-        let batches = self
-            .graph
-            .get_parallel_batches()
-            .map_err(|e| ExecutionError::TaskFailed {
-                task_id: "scheduler".to_string(),
-                message: e,
-            })?;
+        let batches =
+            self.graph
+                .get_parallel_batches()
+                .map_err(|e| ExecutionError::TaskFailed {
+                    task_id: "scheduler".to_string(),
+                    message: e,
+                })?;
 
         let report = Arc::new(Mutex::new(ExecutionReport::new()));
         let errors = Arc::new(Mutex::new(Vec::new()));
@@ -141,13 +137,9 @@ impl<H: TaskHandler + 'static> Executor<H> {
                 template,
             } => self.handler.handle_dotfile(source, target, *template),
 
-            TaskData::Package { name, manager } => {
-                self.handler.handle_package(name, manager)
-            }
+            TaskData::Package { name, manager } => self.handler.handle_package(name, manager),
 
-            TaskData::Secret { source, target } => {
-                self.handler.handle_secret(source, target)
-            }
+            TaskData::Secret { source, target } => self.handler.handle_secret(source, target),
 
             TaskData::Hook { command } => self.handler.handle_hook(command),
 
diff --git a/crates/doot-lang/src/planner/mod.rs b/crates/doot-lang/src/planner/mod.rs
index bec6483..9fc8b87 100644
--- a/crates/doot-lang/src/planner/mod.rs
+++ b/crates/doot-lang/src/planner/mod.rs
@@ -7,5 +7,5 @@ pub mod scheduler;
 pub use dag::DependencyGraph;
 pub use executor::Executor;
 pub use scheduler::{
-    validate_dotfile_targets, DotfileConflict, DotfileValidation, DotfileWarning, Scheduler,
+    DotfileConflict, DotfileValidation, DotfileWarning, Scheduler, validate_dotfile_targets,
 };
diff --git a/crates/doot-lang/src/planner/scheduler.rs b/crates/doot-lang/src/planner/scheduler.rs
index e994b04..4cd9cb5 100644
--- a/crates/doot-lang/src/planner/scheduler.rs
+++ b/crates/doot-lang/src/planner/scheduler.rs
@@ -99,10 +99,7 @@ impl Default for Scheduler {
 #[derive(Debug, Clone)]
 pub enum DotfileConflict {
     /// Same source and target (duplicate entry).
-    Duplicate {
-        index_a: usize,
-        index_b: usize,
-    },
+    Duplicate { index_a: usize, index_b: usize },
     /// Overlapping directories with no distinguishing settings (likely redundant).
     RedundantOverlap {
         parent_index: usize,
@@ -323,7 +320,8 @@ mod tests {
         std::fs::create_dir_all(temp.path().join("config/nvim")).unwrap();
         std::fs::write(temp.path().join("config/nvim/init.lua"), "").unwrap();
 
-        let mut file_dotfile = make_dotfile("config/nvim/init.lua", "/home/user/.config/nvim/init.lua");
+        let mut file_dotfile =
+            make_dotfile("config/nvim/init.lua", "/home/user/.config/nvim/init.lua");
         file_dotfile.template = true;
 
         let dotfiles = vec![
@@ -377,6 +375,10 @@ mod tests {
 
         assert!(result.errors.is_empty());
         assert_eq!(result.warnings.len(), 1);
-        assert!(result.warnings[0].message.contains("overlapping directories"));
+        assert!(
+            result.warnings[0]
+                .message
+                .contains("overlapping directories")
+        );
     }
 }
diff --git a/crates/doot-lang/src/type_checker.rs b/crates/doot-lang/src/type_checker.rs
index 88036de..2a75af3 100644
--- a/crates/doot-lang/src/type_checker.rs
+++ b/crates/doot-lang/src/type_checker.rs
@@ -50,18 +50,26 @@ impl TypeError {
             TypeError::UndefinedType(name, span) => {
                 (format!("undefined type: {}", name), span.clone())
             }
-            TypeError::TypeMismatch { expected, got, span } => {
-                (format!("expected {}, got {}", expected, got), span.clone())
-            }
-            TypeError::NotCallable(ty, span) => {
-                (format!("cannot call non-function type: {}", ty), span.clone())
-            }
+            TypeError::TypeMismatch {
+                expected,
+                got,
+                span,
+            } => (format!("expected {}, got {}", expected, got), span.clone()),
+            TypeError::NotCallable(ty, span) => (
+                format!("cannot call non-function type: {}", ty),
+                span.clone(),
+            ),
             TypeError::FieldNotFound { ty, field, span } => {
                 (format!("field {} not found on {}", field, ty), span.clone())
             }
-            TypeError::WrongArity { expected, got, span } => {
-                (format!("expected {} arguments, got {}", expected, got), span.clone())
-            }
+            TypeError::WrongArity {
+                expected,
+                got,
+                span,
+            } => (
+                format!("expected {} arguments, got {}", expected, got),
+                span.clone(),
+            ),
         };
 
         Report::build(ReportKind::Error, filename, span.start)
@@ -318,7 +326,8 @@ impl TypeChecker {
                         Box::new(ft.return_type.clone()),
                     )
                 } else {
-                    self.errors.push(TypeError::UndefinedVariable(name.clone(), span.clone()));
+                    self.errors
+                        .push(TypeError::UndefinedVariable(name.clone(), span.clone()));
                     Type::Unknown
                 }
             }
@@ -336,7 +345,8 @@ impl TypeChecker {
                                 Type::Int
                             }
                         } else if matches!(op, BinOp::Add)
-                            && (left_ty.is_compatible(&Type::Str) || right_ty.is_compatible(&Type::Str))
+                            && (left_ty.is_compatible(&Type::Str)
+                                || right_ty.is_compatible(&Type::Str))
                         {
                             Type::Str
                         } else {
@@ -349,9 +359,12 @@ impl TypeChecker {
                         }
                     }
 
-                    BinOp::Eq | BinOp::NotEq | BinOp::Lt | BinOp::Gt | BinOp::LtEq | BinOp::GtEq => {
-                        Type::Bool
-                    }
+                    BinOp::Eq
+                    | BinOp::NotEq
+                    | BinOp::Lt
+                    | BinOp::Gt
+                    | BinOp::LtEq
+                    | BinOp::GtEq => Type::Bool,
 
                     BinOp::And | BinOp::Or => {
                         if !left_ty.is_compatible(&Type::Bool) {
@@ -446,7 +459,8 @@ impl TypeChecker {
                     }
                     Type::Unknown | Type::Any => Type::Any,
                     _ => {
-                        self.errors.push(TypeError::NotCallable(callee_ty.display(), span.clone()));
+                        self.errors
+                            .push(TypeError::NotCallable(callee_ty.display(), span.clone()));
                         Type::Unknown
                     }
                 }
@@ -545,7 +559,8 @@ impl TypeChecker {
                 if let Some(et) = self.env.enums.get(enum_name) {
                     Type::Enum(et.clone())
                 } else {
-                    self.errors.push(TypeError::UndefinedType(enum_name.clone(), span.clone()));
+                    self.errors
+                        .push(TypeError::UndefinedType(enum_name.clone(), span.clone()));
                     Type::Unknown
                 }
             }
@@ -572,7 +587,8 @@ impl TypeChecker {
                     }
                     Type::Struct(st)
                 } else {
-                    self.errors.push(TypeError::UndefinedType(struct_name.clone(), span.clone()));
+                    self.errors
+                        .push(TypeError::UndefinedType(struct_name.clone(), span.clone()));
                     Type::Unknown
                 }
             }
@@ -615,8 +631,8 @@ impl TypeChecker {
             }
 
             Expr::Await(expr) => {
-                let ty = self.infer_expr(expr, span);
-                ty
+                
+                self.infer_expr(expr, span)
             }
 
             Expr::Path(left, right) => {
@@ -646,7 +662,7 @@ impl TypeChecker {
     ) -> Type {
         match name {
             "map" | "filter" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     let list_ty = self.infer_expr(&args[0], span);
                     if let Type::List(inner) = list_ty {
                         if name == "filter" {
@@ -660,7 +676,7 @@ impl TypeChecker {
             "fold" => Type::Any,
             "len" => Type::Int,
             "first" | "last" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     let list_ty = self.infer_expr(&args[0], span);
                     if let Type::List(inner) = list_ty {
                         return Type::Optional(inner);
@@ -675,8 +691,11 @@ impl TypeChecker {
             "read_file" | "read_file_lines" => Type::Str,
             "file_exists" | "dir_exists" | "is_symlink" => Type::Bool,
             "list_dir" | "glob" | "walk_dir" => Type::List(Box::new(Type::Path)),
-            "home" | "config_dir" | "config_path" | "data_dir" | "cache_dir" | "temp_dir" | "temp_file" => Type::Path,
-            "path_join" | "path_parent" | "path_filename" | "path_extension" | "read_link" => Type::Path,
+            "home" | "config_dir" | "config_path" | "data_dir" | "cache_dir" | "temp_dir"
+            | "temp_file" => Type::Path,
+            "path_join" | "path_parent" | "path_filename" | "path_extension" | "read_link" => {
+                Type::Path
+            }
             "fetch" | "fetch_json" | "fetch_bytes" | "post" | "post_json" => Type::Any,
             "download" => Type::Bool,
             "exec" | "shell" => Type::Str,
@@ -688,7 +707,7 @@ impl TypeChecker {
             "encrypt_age" | "decrypt_age" => Type::Str,
             "env" => Type::Optional(Box::new(Type::Str)),
             "unwrap" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     let opt_ty = self.infer_expr(&args[0], span);
                     if let Type::Optional(inner) = opt_ty {
                         return *inner;
@@ -706,14 +725,14 @@ impl TypeChecker {
             "is_some" | "is_none" => Type::Bool,
             "all" | "race" => Type::Any,
             "seq" | "batch" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     self.infer_expr(&args[0], span)
                 } else {
                     Type::Any
                 }
             }
             "flatten" | "concat" | "unique" | "sort" | "reverse" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     self.infer_expr(&args[0], span)
                 } else {
                     Type::List(Box::new(Type::Any))
@@ -721,7 +740,7 @@ impl TypeChecker {
             }
             "zip" | "enumerate" => Type::List(Box::new(Type::Any)),
             "sort_by" => {
-                if args.len() >= 1 {
+                if !args.is_empty() {
                     self.infer_expr(&args[0], span)
                 } else {
                     Type::List(Box::new(Type::Any))
diff --git a/crates/doot-lang/src/types.rs b/crates/doot-lang/src/types.rs
index 62636db..9ef3cee 100644
--- a/crates/doot-lang/src/types.rs
+++ b/crates/doot-lang/src/types.rs
@@ -47,7 +47,10 @@ impl Type {
             (a, Type::Optional(b)) => a.is_compatible(b),
             (Type::Function(a_params, a_ret), Type::Function(b_params, b_ret)) => {
                 a_params.len() == b_params.len()
-                    && a_params.iter().zip(b_params.iter()).all(|(a, b)| a.is_compatible(b))
+                    && a_params
+                        .iter()
+                        .zip(b_params.iter())
+                        .all(|(a, b)| a.is_compatible(b))
                     && a_ret.is_compatible(b_ret)
             }
             (Type::Struct(a), Type::Struct(b)) => a.name == b.name,
@@ -71,12 +74,20 @@ impl Type {
             Type::List(inner) => format!("[{}]", inner.display()),
             Type::Optional(inner) => format!("{}?", inner.display()),
             Type::Function(params, ret) => {
-                let params_str = params.iter().map(|p| p.display()).collect::<Vec<_>>().join(", ");
+                let params_str = params
+                    .iter()
+                    .map(|p| p.display())
+                    .collect::<Vec<_>>()
+                    .join(", ");
                 format!("fn({}) -> {}", params_str, ret.display())
             }
             Type::Struct(s) => s.name.clone(),
             Type::Enum(e) => e.name.clone(),
-            Type::Union(types) => types.iter().map(|t| t.display()).collect::<Vec<_>>().join(" | "),
+            Type::Union(types) => types
+                .iter()
+                .map(|t| t.display())
+                .collect::<Vec<_>>()
+                .join(" | "),
             Type::Any => "any".to_string(),
             Type::Unknown => "unknown".to_string(),
         }