codelens-mcp

codelens-mcp

⚠️ Superseded by lens-mcp

codelens has merged into lens-mcp — one MCP server that maps both code and markdown docs. It carries every codelens tool (map, overview, functions, function_body, comments, find, info) unchanged, plus doc tools (outline, heading, links, search) and a unified map that returns a whole project's code structure and doc outlines in one call.

Use lens-mcp instead — git clone https://github.com/segentic-lab/lens-mcp. This repo remains only so existing links resolve; it is no longer developed.

(The description below is retained for reference.)

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Deterministic structural code maps for AI agents. An MCP server (stdio) that gives agents the shape of a codebase — imports, exports, classes, functions, signatures, comments, TODO-markers — without reading whole files into context. Powered by tree-sitter WASM grammars: no native build step, installs anywhere Node 18+ runs.

The contract: codelens is a navigation map. Use it to locate code, then Read the actual source before judging or modifying it. A signature is not the body; an outline is not the section.

Tools

7 read-only tools. Every list in every response is capped, and every cap is reported with an explicit truncated flag — no silent cutoffs.

Tool	What it does
map	Per-file structural overview of a whole directory tree in one call. Skips node_modules, dist, venv, hidden dirs, etc. The orientation tool.
overview	One file's top-level structure: imports, exports, classes (with method names), functions — all with 1-based line/endLine.
functions	Every addressable function in a file — nested functions, methods, getters/setters, class-field arrows, object-literal properties, default exports — with reconstructed signatures, param types, return type, async/exported flags, and parent scope. (Anonymous callbacks passed as arguments and Python lambdas are not listed — they have no name to navigate to.)
comments	All comments with line ranges, kind (line/block/doc), and TODO/FIXME/FIX/BUG/HACK/NOTE/XXX marker detection (uppercase-only, no prose false-positives). markersOnly: true returns just the debt list.
function_body	Verbatim source of one function (with decorators) by bare or dotted name (Widget.render) — the focused read that replaces whole-file Reads. Ambiguous names fail listing the candidates; it never guesses.
find	"Where is X defined?" — locate function/method/class definitions by name across a directory. Definitions only, not call sites.
info	Server self-description: version, working directory (the path sandbox root), languages, caps.

overview, functions, and comments accept a single path or an array of up to 20 paths per call.

Languages

Extension	Language	Grammar
.ts, .mts, .cts	TypeScript	tree-sitter-typescript
.tsx	TypeScript + JSX	tree-sitter-tsx (dedicated grammar — JSX parses correctly)
.js, .jsx, .mjs, .cjs	JavaScript	tree-sitter-javascript
.py	Python	tree-sitter-python

Path sandbox

The server only reads files under its own working directory (the directory it was launched from). Relative paths resolve against it; absolute paths are accepted only if they point inside it; symlinks that escape it are rejected. The info tool reports the root, and every rejection names it. Launch the server from the project you want mapped.

Honesty guarantees

• A file with syntax errors is never reported as a clean success: hasErrors: true plus parseErrors line ranges, because tree-sitter error-recovery can drop code near the error.
• Errors set isError on the MCP result and return {error, path, hint} — the hint says how to fix the call.
• Batch calls return per-file results plus an honest {requested, succeeded, failed} summary; isError only when every file failed.
• Every cap is visible: truncated flags carry the true totals.

Install & run

npm install
npm run build    # tsc → dist/
npm test         # build + 62 tests (51 unit, 11 stdio e2e)
node dist/index.js   # stdio MCP server (launch from the project to analyze)

MCP client config:

{
  "mcpServers": {
    "codelens": {
      "command": "node",
      "args": ["/path/to/codelens-mcp/dist/index.js"],
      "cwd": "/path/to/project-to-analyze"
    }
  }
}

For agent authors

AGENTS.md in this repo is a paste-ready guide for teaching an agent to use these tools well — core model, per-tool tips, and the pitfalls (path sandbox, language coverage, the map-vs-territory rule).

License

AGPL-3.0 — see LICENSE.