Weavatrix

Code graph & blast-radius MCP server for AI coding agents.

Grep sees text. Weavatrix sees structure. It builds a dependency graph of any local repository — files, symbols, and the imports/calls/inheritance connecting them — and serves it to Claude Code, Codex, or any MCP client: change impact, transitive dependents, health audit, clone detection, coverage mapping. 23 tools available; 21 offline tools enabled by default, including one-call repository switching. Local-first: with the defaults, no repository data leaves your machine.

• Website: weavatrix.com

• Source: github.com/sergii-ziborov/weavatrix

• npm: weavatrix — npx -y weavatrix <repoRoot>

Why

An AI agent editing code without the dependency graph is refactoring blind. Weavatrix gives it answers grep can't produce:

• "What breaks if I change this?" → change_impact diffs your branch (staged, unstaged and untracked included), maps the changed files and symbols onto the graph, and lists everything that depends on them — with test coverage attached, so the untested part of the blast radius stands out before you ship.

• "Who calls this function?" → get_dependents walks reverse edges transitively: every caller, importer and subclass that can feel the refactor, ranked by proximity × connectivity.

• "Did my refactor actually decouple anything?" → rebuild_graph + graph_diff report the structural delta: new module dependencies, broken or introduced import cycles, symbols that lost their last caller.

Related MCP server: Axon Pro

Quick start

Requires Node ≥ 18. One command:

# Claude Code — offline default; open_repo can switch local repositories:
claude mcp add -s user weavatrix -- npx -y weavatrix <repoRoot>

Codex CLI:

codex mcp add weavatrix -- npx -y weavatrix <repoRoot>

# or in ~/.codex/config.toml
[mcp_servers.weavatrix]
command = "npx"
args = ["-y", "weavatrix", "C:/path/to/repo"]
startup_timeout_sec = 20
tool_timeout_sec = 60

The default includes offline repository switching but excludes every network tool. Pass a final comma-separated capability list only to restrict or extend it:

# Pin the registration to one repository (hide open_repo/list_known_repos):
claude mcp add -s user weavatrix -- npx -y weavatrix <repoRoot> graph,search,source,health,build

# Add network tools while pinning one repository:
claude mcp add -s user weavatrix -- npx -y weavatrix <repoRoot> graph,search,source,health,build,online

# Add network tools and keep the default repository switching:
claude mcp add -s user weavatrix -- npx -y weavatrix <repoRoot> graph,search,source,health,build,retarget,online

Or clone it:

git clone https://github.com/sergii-ziborov/weavatrix
cd weavatrix && npm install
claude mcp add -s user weavatrix -- node <path-to>/weavatrix/bin/weavatrix-mcp.mjs <repoRoot>

• <repoRoot> — the repository to start with; the graph location is derived automatically (<repoRoot-parent>/weavatrix-graphs/<repoName>/graph.json). Pass an explicit <graph.json> <repoRoot> pair instead if you keep graphs elsewhere.

No graph yet? Ask the agent to call rebuild_graph; it builds the missing graph locally. open_repo can change the active repository and builds a missing graph automatically. A normal open_repo call also upgrades graphs created before 0.1.3 to typed import edges; build:false probes without building and refuses a legacy graph. Retargeting is offline but intentionally changes the filesystem boundary for subsequent tools; omit retarget from an explicit capability list when a registration must stay pinned to one repository.

An agent skill with recipes ships in skill/SKILL.md — install as ~/.claude/skills/weavatrix/SKILL.md.

Tools

graph — graph_stats, get_node, get_neighbors, query_graph, god_nodes, shortest_path, get_community, list_communities, module_map, get_dependents, change_impact, graph_diff. Runtime dependencies and TypeScript type-only coupling are reported separately where that distinction changes the result.

search / source — search_code (ripgrep-backed, pure-Node fallback), read_source (a symbol's actual code in one hop), list_endpoints (HTTP route inventory: Express/Fastify/Nest/Flask/FastAPI/Go mux …)

health — run_audit (dead code, unused exports, missing/unused npm/Go/Python deps, runtime cycles, type-only coupling, orphans, boundary rules, offline OSV vulnerabilities + typosquat + lockfile drift), find_duplicates (MOSS winnowing over method bodies — catches copy-paste even after renames), coverage_map (existing coverage reports mapped onto the graph; untested hotspots ranked by connectivity — tests are never executed)

build — rebuild_graph (reports the structural delta, keeps the prior state as graph.prev.json)

retarget (enabled by default, offline, explicit tool call) — open_repo, list_known_repos; changes the active repository boundary

online (explicit opt-in — see Privacy) — refresh_advisories, sync_graph

Quality of life: graph tools self-report staleness vs the repo HEAD; ambiguous name lookups are disclosed instead of silently guessed; and the server hot-reloads its own tool code when the files under src/mcp/ change — no reconnect needed.

Signal quality and repository configuration

Weavatrix 0.1.3 reduces the most common sources of static-analysis noise:

• In Git repositories, graph and clone scans use tracked plus non-ignored untracked files, so .gitignore-excluded build outputs such as packaged applications do not dominate findings.

• TypeScript import type and type-only re-exports remain visible as compile-time coupling but do not inflate runtime-cycle severity. module_map, change_impact and structural diffs preserve that distinction. god_nodes ranks unique neighbors with runtime connectivity first and reports repeated occurrences separately.

• Dependency checks resolve the nearest workspace manifest and tsconfig/jsconfig aliases, account for framework-owned runtime peers such as Next.js + react-dom, and recognize Next.js App Router route exports as endpoints.

• coverage_map reports coverage as unavailable when no supported report exists. That means “no data”, not zero coverage.

• Duplicate output is a review queue, not a verdict: near-identical bodies are clone candidates; same-name/different-body pairs are divergence candidates. Read both sources and confirm the shared contract before consolidating code.

run_audit makes incomplete security coverage explicit. OSV state is OK only after every supported pinned package/version for this repository was queried successfully. PARTIAL means some queries failed, the response was incomplete, the dependency fingerprint changed, or the cache uses a legacy stamp; NOT_CHECKED means there is no per-repository refresh; ERROR means the local check itself failed. None of the latter three states is a clean vulnerability result. The cache stores a fingerprint of the supported dependency set so a lockfile change cannot silently reuse a stale OK.

For conventions that cannot be inferred safely, add an optional .weavatrix-deps.json at the repository root:

{
  "entrypoints": ["scripts/publish-release.mjs"],
  "python": {
    "managedDependencies": ["numpy", "openvino-genai"],
    "ignoreDependencies": ["vendor-sdk"]
  }
}

entrypoints protects framework/script entry files from dead-code classification. managedDependencies declares Python modules supplied by an external runtime; ignoreDependencies suppresses intentionally unresolved Python packages. Keep the lists narrow: they change audit interpretation, not the repository or its dependency installation.

Privacy: local-first, offline by design

Graph queries, audits, clone scans and repository switching run locally. The default capability set is graph,search,source,health,build,retarget: no Weavatrix HTTP requests. open_repo changes the active local boundary only when called. Weavatrix itself initiates outbound HTTP only from two tools; both require the explicit online group and a tool call:

• refresh_advisories — queries OSV.dev with your lockfile's package names + versions (that is what an OSV query is; never source code) and caches the advisories in ~/.weavatrix/advisories.json. run_audit then matches against that store fully offline.

• sync_graph — constructs a versioned, allowlisted payload from graph.json: relative paths, symbol names and line ranges, import/dependency identifiers, edges and numeric metrics. Unknown fields are discarded; source file bodies are never read for sync or included in the payload. The endpoint is yours, configured via WEAVATRIX_SYNC_URL / WEAVATRIX_SYNC_TOKEN. Off by default. Sync payload v2 preserves type-only edge metadata. Graphs built before 0.1.3 must be rebuilt once before syncing; a normal open_repo call performs that upgrade automatically.

If refresh_advisories is not listed by the MCP client, that is the expected default: the registration does not include online. Only with the user's approval, add online to the final capability list (for example graph,search,source,health,build,retarget,online), restart/reconnect the MCP server, and then invoke refresh_advisories. Enabling the group does not trigger a request by itself.

Capability groups (graph, search, source, health, build, retarget, online) are selectable through the final positional argument. Omitted caps use the safe default above; an explicit list exposes exactly the named groups.

Security model

Socket capability alerts describe expected powers of a local code-analysis tool; they are not vulnerability findings. This is where each capability comes from and how it is controlled:

read_source accepts repo-relative regular files only, caps a read at 2 MB, and refuses lexical or realpath escapes. Graph-derived paths pass through the same boundary before analysis tools read them. Report suspected vulnerabilities privately as described in SECURITY.md.

Languages

JavaScript · TypeScript · TSX · Python · Go · Java · C# · Rust · HTML · CSS — parsed with web-tree-sitter WASM grammars; no Python install, no native compilation.

On-disk layout

Graphs are derived data and never live inside your repo: they go to a weavatrix-graphs/ folder next to it (one folder per repo, holding graph.json + graph.prev.json).

Development

npm install
npm test          # node --test

Design rule: no source file exceeds 300 lines. Larger concerns split into dotted-suffix modules behind a slim facade (foo.js re-exports foo.parse.js, foo.report.js, …); the MCP layer lives in src/mcp/ (graph context, four tool modules, catalog + hot-reload loader) behind the thin stdio entry src/mcp-server.mjs.

Roadmap

• Hosted graph view on weavatrix.com — sync with one tool call, share the interactive map with your team

• Graph-anchored memory — agent notes pinned to nodes/modules, staleness-tracked as the code under them changes

• CI blast radius — change_impact as a PR comment

License

MIT © 2026 Sergii Ziborov