synapse

Synapse

Go-native code context engine for AI IDEs. Synapse indexes repositories via tree-sitter, persists a code graph in an embedded store, and serves context over the Model Context Protocol (MCP)—as a single static binary.

It also indexes OpenAPI 3.x, GraphQL SDL, and Protobuf / gRPC specs into the graph and links handlers/clients across repos with implements / consumes edges.

Requirements

• Go 1.22+ (developed with Go 1.27)
• A C toolchain (CGO required for tree-sitter grammars — see docs/tree-sitter.md)

Supported source languages (batch 1): Go, JavaScript/JSX, TypeScript/TSX, Python, and Swift. Extension map, grammar packages, and extractor completeness: docs/tree-sitter.md. Java, Kotlin, Ruby, PHP, C/C++, and C# are not registered yet.

Install

Install once, then run synapse from any repository.

Go install (recommended)

Requires Go 1.22+ and a C toolchain (CGO / tree-sitter — see docs/tree-sitter.md).

go install github.com/keelwright-hq/synapse/cmd/synapse@latest

Ensure Go’s bin directory is on your PATH. For zsh on macOS:

echo 'export PATH="$HOME/go/bin:$PATH"' >> ~/.zshrc
source ~/.zshrc

Verify:

synapse version

go install embeds the module version from build info (not release ldflags). Tagged GitHub Release binaries stamp Version / Commit / Date explicitly via ldflags.

Upgrade by re-running the same go install …@latest command.

Prebuilt binaries

Download versioned archives for macOS (arm64 / amd64) and Linux (amd64 / arm64) from GitHub Releases. Unpack the archive for your OS/arch, place synapse on your PATH, then run synapse version.

Homebrew

A Homebrew tap/formula is not published yet (follow-up). Use go install or a release binary for now.

Development (from source)

For contributors working in this repo:

git clone https://github.com/keelwright-hq/synapse.git
cd synapse
make build
./synapse version

Ordinary usage does not require cloning or rebuilding from source.

First run

From any target repository (with synapse on your PATH):

synapse --help
synapse version
synapse --repo synapse index .
synapse --repo synapse index . --report
synapse query neighborhood main --root . --json
synapse mcp --root . --repo synapse

Single-repo index writes an embedded Badger graph database under <repo>/.synapse by default (not a human-readable report). That folder is already on Synapse’s ignore list when walking source. Override with --data-dir /tmp/synapse-test for disposable runs. If you indexed an absolute path from outside the repo, pass the same --data-dir (or cd into the repo) for later query / mcp commands.

Pass --report to also write readable dry-run artifacts under <repo>/.synapse-out/ (manifest.json, graph.json, GRAPH_REPORT.md, graph.html). Open .synapse-out/latest/graph.html in a browser for an interactive view; dated subfolders keep history. Details: docs/report.md.

Multi-repo workspace

List members in synapse.yaml, then index and query with --workspace:

version: 1
repos:
  - name: api
    path: ./api
  - name: worker
    path: ./worker

synapse index --workspace . --data-dir .synapse
synapse query neighborhood Handle --workspace . --data-dir .synapse --repo api --json
synapse query neighborhood 'repo://worker/svc/handler.go#func:Handle' \
  --workspace . --data-dir .synapse --json
synapse mcp --workspace . --data-dir .synapse

Details: docs/workspace.md. Cross-repo MCP tools (resolve_api, list_providers, list_consumers): docs/mcp.md.

OpenAPI contracts

On index, Synapse content-sniffs .yaml / .yml / .json for OpenAPI 3.x, creates operation / schema nodes, then heuristically binds:

• implements — handler whose name matches operationId (same repo as the spec)
• consumes — client call sites (path string literals or cross-repo operationId match)

Cross-repo links are stored under {data-dir}/overlay/ and show up in federated workspace queries.

Example with the bundled fixture:

synapse index --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws
synapse query neighborhood 'repo://api/openapi.yaml#operation:GET /users' \
  --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws --json
synapse query neighborhood 'repo://worker/svc/handler.go#func:FetchUsers' \
  --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws --json

Details: docs/openapi.md.

GraphQL contracts

On index, Synapse content-sniffs .graphql / .gql / .graphqls for SDL, creates type / field / operation nodes, then heuristically binds resolvers (same-repo implements, cross-repo consumes) using field-name folds plus common variants (Resolve{Field}, Get{Field}, {Root}_{Field}).

synapse index --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws
synapse query neighborhood 'repo://api/schema.graphql#operation:query users' \
  --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws --json

Details: docs/graphql.md.

Protobuf / gRPC contracts

On index, Synapse content-sniffs .proto for proto3, creates service / operation / schema / field nodes (resolving imports against the repo root), then binds stubs with implements / consumes (method-name folds, {Service}_{Method}, and grpc_path literals).

synapse index --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws
synapse query neighborhood 'repo://api/users.proto#operation:UserService.ListUsers' \
  --workspace testdata/fixtures/workspace --data-dir /tmp/synapse-ws --json

Details: docs/protobuf.md.

Federation / snapshots

Move graph shards between machines with NDJSON snapshots (no cloud required):

synapse graph export --data-dir .synapse --repo api -o api.ndjson
synapse graph import --data-dir /tmp/shards --repo api api.ndjson

# Import under a different logical name (rewrites props.repo_uri)
synapse graph import --data-dir /tmp/shards --repo renamed --rewrite-repo api.ndjson

A mismatched --repo fails by default so shards never keep another repo’s repo_uri. Pass --rewrite-repo to remap props.repo_uri (and URI-keyed overlay endpoints) to the target name.

Federated workspace queries soft-fail missing shards (partial results + warnings). Details: docs/federation.md.

Makefile targets

Docs

License

Apache License 2.0 — see LICENSE.