GitCortex
A local-first, branch-aware code knowledge graph for Git repositories. GitCortex (gcx) indexes your codebase incrementally on every commit using tree-sitter AST parsing, persists the graph in an embedded KuzuDB database, and exposes it to AI coding assistants via an MCP server — in Cursor, Claude Code, Windsurf, GitHub Copilot, and Google Antigravity.
Why
When you ask an AI editor to work on a large codebase, it either scans dozens of files to build context (burning tokens) or misses the bigger picture entirely. There's no middle ground.
GitCortex gives your AI editor a pre-built, queryable call graph of your repo — functions, structs, traits, interfaces, call relationships, inheritance — so instead of reading raw source files it can ask precise questions like "what calls this function?" or "what implements this trait?" and get structured answers instantly.
| GitCortex v0.2 | Others | |
|---|---|---|
| MCP tools | 12, each with real query depth | 4–16 (many shallow grep wrappers) |
| Languages | 5 with full edge coverage (Rust, Python, TS/JS, Go, Java) | Often 1–2, or broad but shallow |
| IDE support | Cursor, Claude Code, Windsurf, Copilot, Antigravity | Usually Claude Code only |
| Index freshness | Automatic on every git commit / merge / rebase / checkout |
Manual re-run |
| Branch graphs | Per-branch, instant switch — no re-index | One graph per repo |
| Install time | cargo install gitcortex + gcx init — under 2 minutes |
Varies |
One sentence: GitCortex is the knowledge graph that stays current without you thinking about it — and works in the editor you already use.
How it works
gcx initinstalls four git hooks and runs an initial full index.- On every local HEAD change the hook fires, diffs only the changed files, and updates the graph in under 500ms.
gcx servestarts an MCP server on stdio so Claude Code (or any MCP client) can query the graph.gcx vizopens an interactive force-directed graph in your browser.
The graph is namespaced per branch — switching branches instantly gives you the graph for that branch with no re-indexing.
Requirements
- Git
- Rust 1.80+ (only needed for source installs — pre-built binaries require nothing)
Installation
macOS / Linux — pre-built binary (no Rust required):
|
Pre-built binaries for macOS (arm64/x86_64) and Linux (x86_64/aarch64) are published automatically on every release via GitHub Releases. Windows users should build from source (see below) — a prebuilt binary will ship in a future release.
Cargo (from crates.io):
Cargo (from git — works before crates.io publish):
Build from source:
Quick start
That installs the git hooks and indexes the current branch. Every subsequent commit updates the graph automatically.
Commands
gcx init
Installs four git hooks, runs the initial full index, registers the MCP server in the detected editor(s), and writes .gitcortex/AGENT_GUIDE.md as a universal context file.
Output:
GitCortex initialised (820ms)
Graph: 2 141 nodes | 5 328 edges
Hooks: 4 git hooks installed
Editors: Cursor, Claude Code (auto-detected)
Universal: .gitcortex/AGENT_GUIDE.md
| Editor | Files written |
|---|---|
| Claude Code | .claude/hooks/, .claude/settings.json, .claude/skills/, .claude/commands/, ~/.claude.json |
| Cursor | .cursor/rules/gitcortex.mdc, .cursor/mcp.json |
| Windsurf | .windsurfrules, ~/.codeium/windsurf/mcp_config.json |
| Copilot | .github/copilot-instructions.md |
| Antigravity | ~/.antigravity/mcp.json |
gcx hook
Called automatically by the git hooks — you rarely invoke this directly.
gcx serve
Starts the MCP server on stdio. Wire this up in your .mcp.json to give Claude Code access to the knowledge graph.
gcx query
One-shot CLI queries for manual inspection.
gcx viz
Visualise the knowledge graph.
The browser UI is built on Cytoscape.js with a Catppuccin dark theme. Features:
- Community detection — nodes grouped by label-propagation clusters, each cluster shaded a distinct fill
- Node sizing by LOC (lines of code); edge colour by edge kind
- Filter rail — NodeKind toggles, EdgeKind toggles, visibility (pub / pub(crate) / private), file list, async/unsafe flag toggles
- Search bar — fuzzy match by name or qualified name, ↑/↓/Enter keyboard navigation
- Inspector panel — callers, callees, and uses/implements lists with click-to-navigate
- Trace path — type any target symbol; BFS path highlighted with animation
- Layout switcher — Force (cose), Concentric, Tree (breadthfirst)
gcx blast-radius
Show which callers are affected by changes between two branches. Powers the PR comment bot.
Example output (--format text):
Blast Radius Report
────────────────────────────────────────────────────
feat/auth → main
Changed: 2 | Affected: 8 | Risk: MEDIUM
────────────────────────────────────────────────────
Changed nodes:
function validate_token src/auth.rs:23
method build_claims src/auth.rs:54
Affected callers:
[hop 1] function handle_request src/handler.rs:8
[hop 1] function middleware_chain src/middleware.rs:3
[hop 2] function router src/main.rs:12
...
gcx export
Generates .gitcortex/context.md — a readable Markdown codebase map organized by file with hierarchical struct→method containment. Once generated, the git hook keeps it fresh after every commit.
Example output:
- - --
-
Commit .gitcortex/context.md to give teammates (and Claude) instant codebase context without an MCP server.
gcx status
Show node and edge counts for the current branch.
branch: main
last sha: abc1234...
nodes: 312
function 80
method 69
struct 22
...
edges: 847
calls 514
contains 246
...
gcx clean
Wipe the graph store for this repo so the next gcx init or commit triggers a full re-index.
CI / PR blast radius bot
This writes .github/workflows/gcx-blast-radius.yml. On every pull request it runs gcx blast-radius and posts the result as a sticky PR comment using the github-comment format.
MCP integration
gcx init registers the MCP server in ~/.claude.json — no per-project config needed. The server is available in every Claude Code session on this machine automatically.
Available MCP tools
| Tool | Description |
|---|---|
lookup_symbol |
Find all nodes matching a name across the codebase |
find_callers |
All functions that call a given function (backward trace) |
find_callees |
All functions called by a given function (forward trace, configurable depth) |
list_definitions |
All definitions in a source file ordered by line |
find_implementors |
All structs/classes that implement a trait or interface |
trace_path |
Every call path between two symbols (up to 6 hops) |
list_symbols_in_range |
Symbols whose span overlaps a file + line range |
find_unused_symbols |
Symbols with zero callers — dead code candidates |
get_subgraph |
All nodes + edges within N hops of a seed symbol (in/out/both) |
branch_diff_graph |
Nodes added or removed between two branches |
detect_changes |
Changed symbols + blast radius vs a base branch |
symbol_context |
Callers, callees, and used-by for a symbol |
All tools accept an optional branch parameter (defaults to "main").
Claude Code slash commands
gcx init installs four slash commands into .claude/commands/gcx/ that are immediately available in Claude Code:
| Command | What it does |
|---|---|
/gcx-lookup <name> |
Find all definitions matching a name |
/gcx-callers <name> |
Find all callers of a function |
/gcx-file <path> |
List all definitions in a file |
/gcx-blast-radius |
Show blast radius of changes vs main |
Configuration
.gitcortex/config.toml
Committed to the repo and shared with your team.
[]
= ["rust", "typescript", "python", "go"]
= 500
[]
= false # pass-2 LLD annotation (v0.2)
[]
= "local" # local only in v0.1; remote backend planned
.gitcortex/ignore
.gitignore-syntax patterns for files to exclude from indexing.
target/
build/
**/*.generated.rs
**/*.pb.rs
Graph schema
Node kinds
| Kind | Languages | Description |
|---|---|---|
File |
all | Source file |
Module |
all | mod foo { }, Python module, Go package |
Struct |
Rust/Go/TS/Java | struct Foo, class Foo |
Enum |
all | enum Bar |
Trait |
Rust/Python | trait Baz, Protocol |
Interface |
TS/Go/Java | interface Foo, structural interface |
TypeAlias |
Rust/TS/Python | type Alias = ... |
Function |
all | Free-standing function |
Method |
all | Method inside a class / impl block |
Constant |
all | const / static |
Macro |
Rust | macro_rules! or proc-macro |
Property |
TS/Python | Class property, @property |
Annotation |
Java | @interface annotation type |
EnumMember |
all | Variant inside an enum |
Edge kinds
| Kind | Description |
|---|---|
Contains |
Parent–child: File→Module, Struct→Method |
Calls |
Resolved call site: Function→Function |
Implements |
impl Trait for Struct, class implements interface |
Inherits |
extends / embedded struct / sealed permits |
Uses |
Type appears as parameter or return type |
Imports |
use path::to::Thing, import |
Throws |
Java throws clause → exception type |
Annotated |
Node decorated by #[attr], @decorator, @annotation |
Node metadata flags
Every node carries: loc, visibility (Pub / PubCrate / Private), is_async, is_unsafe, is_static, is_abstract, is_final, is_const, is_property, is_generator, and generic_bounds.
Data storage
The graph database is stored locally and never committed:
~/.local/share/gitcortex/{repo_id}/
graph.kuzu # KuzuDB database (all branches, namespaced by table prefix)
main.sha # last indexed SHA for branch "main"
feat__auth.sha # last indexed SHA for branch "feat/auth"
Architecture
flowchart TD
subgraph repo["Your Repository"]
hooks["git hooks\npost-commit · post-merge · post-rewrite · post-checkout"]
files["Source Files — .rs · .ts · .py · .go"]
end
subgraph indexer["gitcortex-indexer"]
differ["git2 differ\nchanged files only"]
parsers["tree-sitter parsers\nRust · TypeScript · Python · Go"]
differ --> parsers
end
kuzu[("KuzuDB\nbranch-namespaced\ngraph store")]
subgraph gcx["gitcortex-mcp · gcx"]
server["MCP server\nlookup_symbol · find_callers\nlist_definitions · branch_diff_graph"]
blast["gcx blast-radius\nrisk scoring · PR comment"]
viz["gcx viz\nbrowser graph · DOT export"]
end
claude["Claude Code\nMCP tools · slash commands · skills"]
gh["GitHub Actions\nsticky PR blast-radius comment"]
hooks -->|"gcx hook — incremental diff"| differ
files --> differ
parsers -->|"GraphDiff\nnodes + edges"| kuzu
kuzu --> server
kuzu --> blast
kuzu --> viz
server --> claude
blast --> gh
The GraphStore trait is the extensibility boundary — the local KuzuDB backend can be swapped for a remote backend without touching the indexer or MCP layer.
License
MIT