pi-file-tree

A pi extension that adds a file-tree aside panel with treesitter symbol extraction powered by your existing neovim installation.

Features

• File tree aside — right-anchored overlay (40% width, full height) that keeps your prompt visible
• Treesitter symbols — expand code files to see functions, classes, structs, enums, interfaces, methods with line numbers
• Zero extra dependencies — uses your neovim's already-installed treesitter parsers (.so grammars)
• Parser auto-detection — scans ~/.local/share/nvim/site/parser/ and nvim runtime paths on every open; install a new :TSInstall grammar and it's immediately available
• fzf integration — when fzf is on $PATH, /files with no argument opens a fuzzy directory picker; partial args are fuzzy-matched via fzf --filter
• Multi-select — pick multiple files and symbols with Space; selections are appended to your pi prompt on close
• Parent navigation — .. entry at the top of the tree; Enter on it re-roots to the parent directory

Installation

Clone into your pi extensions directory:

git clone https://github.com/YOUR_USER/pi-file-tree ~/.pi/agent/extensions/file-tree

Or symlink from a working copy:

git clone https://github.com/YOUR_USER/pi-file-tree ~/CODE/pi-file-tree
ln -s ~/CODE/pi-file-tree ~/.pi/agent/extensions/file-tree

Then /reload in pi.

Requirements

• pi coding agent
• neovim (on $PATH) with treesitter parsers installed — the extension works without nvim but symbol extraction is disabled
• fzf (optional) — enables fuzzy directory picking

Usage

Commands

Command	Description
/files	Open file tree at project root. If fzf is available, shows a fuzzy directory picker first.
/files src/utils	Open file tree rooted at src/utils/
/files util	Fuzzy-match util against all directories (requires fzf)

Keyboard shortcut

Key	Description
Alt+C	Open file tree aside (from pi prompt)

Navigation inside the aside

Key	Action
↑ ↓	Navigate
Enter	Expand/collapse — directories toggle, .. goes up, files with parser show symbols
← →	Fold / unfold (same as Enter, plus Left jumps to parent)
Space	Toggle selection on file, directory, or symbol
Ctrl+U Ctrl+D	Half-page scroll
Home End	Jump to top / bottom
Esc or q	Close aside — selected items are appended to your pi prompt

Visual indicators

Icon	Meaning
▸ / ▾	Collapsed / expanded directory or file
← ..	Parent directory navigation
ƒ	Function
●	Class
■	Struct
◆	Enum
◇	Interface / type
→	Method
◈	Module
◉	Const / static
✔	Selected (green)

How it works

Treesitter detection

On each aside open, the extension:

1. Checks for nvim on $PATH
2. Scans standard parser directories for .so / .dylib / .dll grammars:
   • ~/.local/share/nvim/site/parser/
   • ~/.local/share/nvim/lazy/nvim-treesitter/parser/
   • Any additional paths reported by nvim --headless via vim.api.nvim_get_runtime_file()
3. Maps file extensions to parser names (40+ languages supported)
4. Files with a matching parser show the ▸ expand affordance

Symbol extraction

When you expand a code file, the extension runs:

nvim --headless --noplugin -n <file> -c "luafile symbols.lua"

The symbols.lua script:

• Detects filetype via vim.bo.filetype
• Maps filetype to treesitter language (with a built-in fallback table for --noplugin mode, e.g. typescriptreact → tsx)
• Walks the AST looking for definition nodes (functions, classes, structs, enums, interfaces, methods, etc.)
• Outputs a JSON array of { name, kind, line } to stdout
• Deduplicates by name+line

Symbols are cached per-file for the lifetime of the aside.

Supported languages

Any language with a neovim treesitter parser installed. The extension maps these file extensions to parser names:

.ts .tsx .js .jsx .py .rs .go .lua .c .h .cpp .java .kt .rb .sh .json .yaml .toml .md .html .css .vim .xml .sql .zig .ex .erl .hs .ml .swift .dart .r .scala .svelte .vue .tf .nix

File structure

file-tree/
├── index.ts       # Pi extension — command, shortcut, TUI component, fzf/treesitter integration
├── symbols.lua    # Neovim lua script — treesitter symbol extraction
└── README.md

License

MIT