@prom.codes/context-mcp

prom.codes Context — local-first codebase indexing & retrieval as an MCP server (stdio).

Quick start (Claude Code)

claude mcp add context --env PROMETHEUS_API_KEY=prom_live_… -- npx -y @prom.codes/context-mcp@latest

claude mcp add defaults to local scope (just you); add --scope project to write a committable .mcp.json, or --scope user for all your projects. Other MCP hosts (Cursor, VS Code) use the same command/args in their own config.

Configuration

• PROMETHEUS_API_KEY (required for semantic search) — a real key minted at app.prom.codes/app/api-keys, shape prom_live_<tag>_<secret>. Embeddings route through the managed prom.codes proxy — you never bring your own provider key. Without a valid key, code search degrades gracefully to lexical (keyword) + symbol-graph retrieval (no embeddings needed) and every structural tool still works.
• Workspace root is auto-detected — no need to set PROMETHEUS_WORKSPACE_ROOT. Claude Code passes the open project via CLAUDE_PROJECT_DIR; Cursor/VS Code via the MCP roots capability. Set it only to point at a different folder.
• The index is a local SQLite DB at ~/.prometheus/<hash>.db (one per project). Your code never leaves your machine — only embedding text transits to the proxy.
• Won't crawl your home folder. If a fresh window opens with no project, the workspace falls back to the host cwd (often home); the server refuses to auto-index the home directory or a filesystem root and leaves the index empty until you open a real project. Call index_status to see what's going on.

Tools: search_code, get_symbol, find_references, find_callers, find_callees, expand_context, get_file, list_changed_since, list_workspaces, framework_overview, index_status (health check: which folder, how much is indexed, does the key work?).

Native modules

Uses native Tree-sitter grammars + better-sqlite3 for parsing and storage. Prebuilt binaries are fetched automatically on the mainstream platforms (macOS x64/arm64, Linux x64, Windows x64) — no compiler needed. On other platforms (e.g. Linux/Windows arm64) or a Node ABI without a prebuild, install C/C++ build tools so the native modules can compile (Windows: VS Build Tools). If npx skips the native build under a hardened npm (ignore-scripts=true), install globally once and point Claude Code at the built binary — see the docs. Requires Node ≥ 20.10.

Docs: https://prom.codes/docs/mcp/claude-code