🌳 Tree-sitter Analyzer

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The MCP code-intelligence server for AI agents — fewer tokens, fewer tool calls, 100 % local. Pre-indexed AST cache + 62 MCP tools + 13 curated agent skills + TOON-compressed output. Beats CodeGraph on 6-repo head-to-head median (−11 % cost vs CodeGraph's −4 %), with a strict CLI superset. Now with BM25-ranked symbol search across all 62 tools — results sorted by relevance, not file path.

Get Started

One-line install for Claude Code:

claude mcp add tree-sitter-analyzer \
  --env TREE_SITTER_PROJECT_ROOT="$PWD" \
  -- uvx --from "tree-sitter-analyzer[mcp]" tree-sitter-analyzer-mcp

Restart your agent, then say: "Set the project root to my repo and run codegraph_status."

Other agents (Cursor, Copilot, Cline, Continue, Claude Desktop, Roo Code) →

Why Tree-sitter Analyzer

• Token-efficient by default. Every MCP response uses TOON — a tabular JSON variant that cuts payload by ~50-70 % vs raw JSON.

• Verdict envelopes. Every response carries verdict: SAFE | CAUTION | UNSAFE | INFO | WARN | ERROR | NOT_FOUND, so orchestrators branch on outcomes without re-prompting.

• Project health grading (A–F). No other open-source tool grades your whole project on size / complexity / coverage / duplication / dependencies / structure / git-hotspots in one call.

• 13 curated workflows (Skills). Pre-baked tool subsets for "find symbol", "trace call chain", "score health", "safe-to-edit before refactor", "PR review", etc.

• 5 layers of safety. safe_to_edit + modification_guard + constraint DSL + change_impact + verdict envelopes — designed so agents know before they touch.

• Beats the leading competitor (CodeGraph) on multiple head-to-head benchmarks. See below.

Benchmark Results

Headless Claude Code (Haiku 4.5) asked one architecture question per repo. 3 arms: no-MCP / CodeGraph MCP / Tree-sitter Analyzer MCP. Single run per arm — indicative, not statistically settled.

TSA wins outright on 2 of 6 repos, has a lower median cost saving (−11 %), and matches CodeGraph's reported direction on every repo where the indexer-class tools should help.

Why the median diverges from CodeGraph's published −35 % claim: we used Haiku for cost control; they used Opus + 4-run median. See docs/internal/CODEGRAPH_BENCHMARK_FINAL_2026-05-24.md for raw envelopes + reproducer scripts.

Post-benchmark improvements (2026-05-30): (1) BM25 pre-filter narrows 40k symbols to ~400 before cosine rerank — a 133× speedup in semantic search. (2) Min-max BM25 normalization: relevance_score now properly differentiates strong matches (1.0) from weak (0.0) across all search paths. (3) semantic().sort(by='confidence') now works end-to-end. These improvements were not in the benchmark run; repos with large symbol counts (Django, Excalidraw) should see improved token efficiency in re-runs.

Key Features

Pre-indexed code intelligence (CodeGraph parity + superset)

Tree-sitter Analyzer exclusive

Skills (13 curated workflows)

CodeGraph has zero skills. We ship 13 under .claude/skills/tsa-*/:

tsa-landing, tsa-find, tsa-graph, tsa-structure, tsa-deps, tsa-index, tsa-health-watch, tsa-edit-safety, tsa-edit-then-verify, tsa-constraints, tsa-pr-review, tsa-refactor-queue, tsa-temporal.

Each skill ships an allowed-tools subset + procedure recipe + decision-surface schema, so the agent doesn't have to triage 62 tools on every question.

255 CLI flags

Strict superset of CodeGraph's 15-command CLI. Highlights:

tree-sitter-analyzer --table full <file>          # method/signature/complexity table
tree-sitter-analyzer --partial-read --start-line N --end-line M <file>
tree-sitter-analyzer --project-health             # A-F grade across the project
tree-sitter-analyzer --callers <symbol>           # who-calls
tree-sitter-analyzer --codegraph-impact <fn>      # blast radius + risk
tree-sitter-analyzer --affected <file...>         # tests transitively affected
tree-sitter-analyzer --dead-code                  # transitive unreachable
tree-sitter-analyzer --check-constraints          # architectural rules
tree-sitter-analyzer --safe-to-edit <file>        # refuse if risky
tree-sitter-analyzer --uml class                  # Mermaid UML class diagram

See docs/CODEMAPS/cli.md for the full surface.

Quick Start

1. Install dependencies

# uv (required)
curl -LsSf https://astral.sh/uv/install.sh | sh        # macOS / Linux
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"  # Windows

# fd + ripgrep (required for search)
brew install fd ripgrep                                # macOS
winget install sharkdp.fd BurntSushi.ripgrep.MSVC      # Windows

2. Install Tree-sitter Analyzer

uv add "tree-sitter-analyzer[all,mcp]"

3. Hook it into your agent

See Supported Agents. Most clients want this MCP server entry:

{
  "mcpServers": {
    "tree-sitter-analyzer": {
      "command": "uvx",
      "args": ["--from", "tree-sitter-analyzer[mcp]", "tree-sitter-analyzer-mcp"],
      "env": { "TREE_SITTER_PROJECT_ROOT": "/absolute/path/to/your/project" }
    }
  }
}

After restart: "Set the project root to my repo and call codegraph_status."

How It Works

Source code → tree-sitter parse → SQLite + FTS5 index (.ast-cache/index.db)
                                         ↓
        codegraph_navigate / codegraph_explore / codegraph_callers / ...
                                         ↓
                            TOON-compressed envelope
                            (verdict + agent_summary + data)
                                         ↓
                              MCP client / CLI consumer

The index is built lazily on first query, refreshed on file change via a content-hash diff (codegraph_incremental_sync). All 62 tools read from the same .ast-cache/, so a query and its follow-up share work.

Supported Agents

claude mcp add tree-sitter-analyzer \
  --env TREE_SITTER_PROJECT_ROOT="$PWD" \
  -- uvx --from "tree-sitter-analyzer[mcp]" tree-sitter-analyzer-mcp

Verify: claude mcp list. The 13 tsa-* skills auto-discover from .claude/skills/.

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\, Linux: ~/.config/Claude/):

{
  "mcpServers": {
    "tree-sitter-analyzer": {
      "command": "uvx",
      "args": ["--from", "tree-sitter-analyzer[mcp]", "tree-sitter-analyzer-mcp"],
      "env": { "TREE_SITTER_PROJECT_ROOT": "/absolute/path/to/your/project" }
    }
  }
}

Create .vscode/mcp.json (note: servers, not mcpServers):

{
  "servers": {
    "tree-sitter-analyzer": {
      "type": "stdio",
      "command": "uvx",
      "args": ["--from", "tree-sitter-analyzer[mcp]", "tree-sitter-analyzer-mcp"],
      "env": { "TREE_SITTER_PROJECT_ROOT": "${workspaceFolder}" }
    }
  }
}

All read the same mcpServers schema as Claude Desktop. Cursor: Settings → MCP. Cline: MCP panel → Edit settings. Continue: ~/.continue/config.json under experimental.modelContextProtocolServers. Roo Code: MCP panel → Edit MCP Settings.

⚠️ TREE_SITTER_PROJECT_ROOT must be absolute. The server enforces a security boundary against escapes via SecurityBoundaryManager.

Supported Languages

21 language plugins; 13 fully wired into the indexer (full symbol + call graph) + 5 (data/markup) reachable via the single-file CLI path + 3 scaffold (plugin exists, indexer wiring pending). The 2026-05-24 patch unblocked Swift / Kotlin / Ruby / PHP / C# that had been silently skipped for months.

CodeGraph supports a similar set; the only popular code languages neither tool ships yet are Dart, Vue, Svelte, Lua (next-sprint backlog).

Configuration

Mostly nothing. The defaults are designed so you can hook it into your agent and forget:

• Output format: TOON. Override per-call with output_format: "json".

• Project root: TREE_SITTER_PROJECT_ROOT (env var, MCP) or --project-root (CLI).

• Cache location: <project>/.ast-cache/. Safe to delete — auto-rebuilds.

• Optional: TREE_SITTER_OUTPUT_PATH for large-output write target.

Quality & Testing

uv run pytest -q                                # full suite
uv run python check_quality.py --new-code-only  # quality gate

Troubleshooting

Development

git clone https://github.com/aimasteracc/tree-sitter-analyzer.git
cd tree-sitter-analyzer
uv sync --extra all --extra mcp
uv run pytest -q

See docs/CONTRIBUTING.md for the development guide.

Contributing & License

• ⭐ A GitHub star helps surface this tool to other AI-agent users.

• 💖 Sponsor — supports continued MCP / Skills development.

• Lead sponsor: @o93.

• MIT licensed — see LICENSE.

• Release history: CHANGELOG.md.