RepoGraph

A local-first code intelligence graph for Python repos, exposed over MCP so agents like Claude Code can query it instead of re-reading the whole codebase every session.

Coding agents don't remember your repo's structure between sessions. Ask one to change a function and it either greps around or reads a pile of files just to figure out what calls what. RepoGraph parses your repo once with tree-sitter, builds a typed graph of functions/classes/modules and their calls/imports/inherits/tests relationships, and keeps it updated incrementally from git diffs. Agents then query it directly: "what calls this?", "what breaks if I change this?" — without touching the rest of the repo.

What it gives you

Three MCP tools:

• get_subgraph(entity, depth) — the neighborhood around a function/class/module

• find_callers(fn) — who calls this, directly

• find_impact(fn) — the full blast radius: everyone who transitively calls or tests it

Plus two resources (repograph://schema, repograph://stats), a reviewer agent that pulls just the blast radius of a diff before asking Claude to review it, and a graph-maintainer agent that flags orphaned code and modules with too many dependents.

Related MCP server: Lore MCP Server

How it's built

git repo
  │  tree-sitter parse (full) / git diff (incremental)
  ▼
graph builder — nodes: module/class/function, edges: imports/inherits/calls/tests
  ▼
SQLite + NetworkX (local, no server, easy to inspect)
  ▼
FastMCP server — get_subgraph / find_callers / find_impact
  │                                        │
  ▼                                        ▼
reviewer agent                    graph-maintainer agent

Python 3.11+, single language for now (the parser/graph-builder split is where a second tree-sitter grammar would plug in). Full stack: tree-sitter, NetworkX, SQLite, FastMCP, GitPython, the Claude API for the two agents, pytest for everything else.

Setup

python3.11 -m venv .venv
.venv/bin/pip install -e ".[dev]"

Build a graph and run the server:

.venv/bin/repograph-build /path/to/some/repo --db repograph.db
.venv/bin/repograph-mcp repograph.db

--incremental re-runs against the last indexed commit instead of parsing everything again.

Adding it to Claude Code

claude mcp add repograph -- /absolute/path/to/repograph/.venv/bin/repograph-mcp /absolute/path/to/repograph.db

or drop this into a project's .mcp.json (see .mcp.json.example):

{
  "mcpServers": {
    "repograph": {
      "command": "/absolute/path/to/repograph/.venv/bin/repograph-mcp",
      "args": ["/absolute/path/to/repograph.db"]
    }
  }
}

Then just ask it to check find_impact before touching something.

Does it actually work? (the evaluation harnesses)

Most "code graph" tools ship a headline number with nothing backing it up. Every claim here is a test, not a paragraph:

.venv/bin/pytest -q

Context reduction on the bundled fixture repo

This is a ~10-function fixture repo, not a real production codebase, so treat the exact percentages as illustrative. Point the benchmark at any real repo to regenerate it:

.venv/bin/python scripts/benchmark.py --repo /path/to/some/repo --out README.md

CI does this automatically on every push (.github/workflows/ci.yml).

Where it falls short

Symbol resolution is a static heuristic, not real type inference, and it's tuned to favor precision over recall:

• Dynamic dispatch isn't resolved. s.area() where s could be any subclass produces no edge rather than a guess. That's deliberate — see the fixture's compute_total_area, which is the one call the correctness harness expects to miss.

• self.method() resolves to whatever's defined on the enclosing class, not to whichever override would actually run.

• Decorator arguments aren't parsed for calls — @app.route("/x") won't create an edge to app.route.

• Only same-repo imports get nodes. Calls into stdlib/third-party code are correctly left unresolved instead of invented.

The graph-maintainer's orphan detection inherits this: a method whose only real caller is dynamic dispatch will look "orphaned" even though it isn't. It's documented in tests/test_maintainer_agent.py, not hidden.

Layout

src/repograph/
  parser.py            tree-sitter extraction, one file at a time
  graph_builder.py      cross-file symbol resolution -> graph
  store.py               SQLite persistence
  git_integration.py     incremental updates from git diffs
  queries.py              get_subgraph / find_callers / find_impact
  benchmark.py            context-reduction measurement
  mcp_server.py           FastMCP server
  cli.py                  repograph-build
  agents/reviewer.py, maintainer.py
tests/
  fixtures/               hand-crafted sample repo + golden JSON
  ast_reference.py        independent ast-based ground truth
  test_*.py               one file per harness, plus MCP/agent/CLI tests