rust-faf-mcp

MCP server for FAF — structured AI project context in YAML (application/vnd.faf+yaml).

Single binary, stdio transport, 4.3 MB stripped. Built on rmcp and faf-rust-sdk.

Install

# From crates.io
cargo install rust-faf-mcp

# Or via Homebrew (macOS, pre-built)
brew install Wolfe-Jam/faf/rust-faf-mcp

Configure

Claude Code

claude mcp add faf rust-faf-mcp

WARP / Cursor / Zed / Claude Desktop

Any MCP client that supports stdio:

{
  "mcpServers": {
    "faf": {
      "command": "rust-faf-mcp"
    }
  }
}

No flags, no config files, no network listener. Pure stdio JSON-RPC.

Tools

Tool	What it does
`faf_init`	Create or enhance `project.faf` from `Cargo.toml`, `package.json`, `pyproject.toml`, or `go.mod`
`faf_read`	Parse and display `project.faf` contents
`faf_score`	Score AI-readiness 0–100% with field-level breakdown
`faf_sync`	Sync `project.faf` → `CLAUDE.md` (preserves existing content)
`faf_git`	Generate `project.faf` from a GitHub repo URL via API
`faf_compress`	Compress `.faf` for token-limited contexts (`minimal` / `standard` / `full`)
`faf_discover`	Walk up the directory tree to find the nearest `project.faf`
`faf_tokens`	Estimate token count at each compression level

faf_init is iterative — run it again and it fills in what's missing. Score goes up each time.

Resources

URI	Content
`faf://scoring/weights`	Scoring weight breakdown as JSON

Architecture

src/
├── main.rs      # ~20 lines — tokio entry, rmcp stdio transport
├── server.rs    # FafServer: #[tool_router], ServerHandler, resources
└── tools.rs     # Business logic — all 8 tools, pure functions returning Value

Runtime: tokio single-threaded (current_thread)
HTTP: reqwest async (only used by faf_git for GitHub API)
SDK: faf-rust-sdk 1.3 for parsing, validation, compression, discovery
Server: rmcp 1.1 with #[tool_router] macro — handles JSON-RPC, schema generation, transport

Tools return serde_json::Value. The server adapts them to Result<String, String> for rmcp's IntoCallToolResult.

Testing

91 tests across 5 files:

cargo test    # runs all 91

File	Tests	Coverage
`mcp_protocol.rs`	9	Init handshake, tools/list, resources, schema validation, ID preservation
`tools_functional.rs`	25	All 8 tools — happy path, error paths, language detection
`tier1_security.rs`	12	Path traversal, null bytes, shell injection, oversized input, malformed JSON
`tier2_engine.rs`	35	Corrupt YAML, sync replacement, pipelines, dual manifests, legacy filenames, direct paths
`tier3_edge_cases.rs`	10	Unicode, CJK, score boundaries, unknown fields, GitHub URL parsing

Tests spawn the compiled binary as a subprocess and communicate via stdin/stdout JSON-RPC — true integration tests against the real server.

Build from source

git clone https://github.com/Wolfe-Jam/rust-faf-mcp
cd rust-faf-mcp
cargo build --release
# Binary at target/release/rust-faf-mcp (4.3 MB)

Edition: 2021 | LTO: enabled | Strip: symbols

License

MIT

rust-faf-mcp

rust-faf-mcp

Install

Configure

Claude Code

WARP / Cursor / Zed / Claude Desktop

Tools

Resources

Architecture

Testing

Build from source

Links

License

Reviews