🤖 Add file_list tool with recursive structure

[ammar-agent]

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Summary

Adds file_list tool for directory exploration without spawning bash processes. Returns recursive JSON tree structure that models can easily interpret.

Key Features

Recursive structure: Results nest via children arrays - models see hierarchy directly without parsing paths.

Gitignore by default: Respects .gitignore patterns automatically (.git always hidden). Set gitignore: false to see all files.

Pattern filtering: Glob support (*.ts, **/*.test.ts). Prunes empty directories when patterns are used.

Limit enforcement: 128 entry hard cap. Fails with actionable error message instead of truncating (matches bash tool philosophy).

UI: Tree visualization with file sizes and proper indentation.

Implementation

• Core: src/services/tools/file_list.ts (273 lines)
• Tests: 18 test cases covering recursion, filtering, limits, gitignore, errors
• Dependencies: Added minimatch (glob), ignore (.gitignore parsing)
• UI: FileListToolCall component with CSS modules

Example Usage

// Quick scan (depth 1, default)
file_list({ path: "src/components" })

// Find TypeScript files
file_list({ 
  path: "src", 
  pattern: "*.ts",
  max_depth: 3,
  max_entries: 50 
})

// Show all files (ignore .gitignore)
file_list({ 
  path: ".", 
  gitignore: false 
})

Testing

bun test src/services/tools/file_list.test.ts  # 18/18 pass
make typecheck  # ✓
make fmt-check  # ✓