OpenGrok MCP Server

What the code does

We read the source, 22 h ago · rules 3dff92dd89df

What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.

    const filePath = path.join(memoryBank.bankDir, filename);

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Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

claude mcp add opengrok-mcp-server -- npx -y opengrok-mcp-server

{
  "mcpServers": {
    "opengrok-mcp-server": {
      "args": [
        "-y",
        "opengrok-mcp-server"
      ],
      "command": "npx"
    }
  }
}

[mcp_servers.opengrok-mcp-server]
command = "npx"
args = ["-y", "opengrok-mcp-server"]

{
  "mcpServers": {
    "opengrok-mcp-server": {
      "args": [
        "-y",
        "opengrok-mcp-server"
      ],
      "command": "npx"
    }
  }
}

{
  "mcpServers": {
    "opengrok-mcp-server": {
      "args": [
        "-y",
        "opengrok-mcp-server"
      ],
      "command": "npx"
    }
  }
}

This one needs environment variables set before it will start: OPENGROK_BASE_URL (OpenGrok server base URL (e.g. https://opengrok.example.com/source/)), OPENGROK_USERNAME (OpenGrok authentication username. Leave unset for anonymous access.), OPENGROK_PASSWORD (OpenGrok authentication password. Prefer storing via OS keychain using 'npx opengrok-mcp-server setup'.), OPENGROK_VERIFY_SSL (Verify TLS certificates. Set to false for self-signed or internal CA certs.), OPENGROK_CODE_MODE (Enable Code Mode: 2-tool sandbox interface with env.opengrok.* JavaScript API. Reduces AI token usage by ~90%.), OPENGROK_ENABLE_MEMORY_TOOLS (Register the 3 memory tools in Code Mode (memory status, read, update). Off = api + execute only.), OPENGROK_DEFAULT_PROJECT (Default project to scope all searches. Can be overridden per call.), OPENGROK_CONTEXT_BUDGET (Response size tier controlling token usage.), OPENGROK_API_VERSION (OpenGrok REST API version. Use v2 for call graph features (requires OpenGrok 1.12+).), HTTP_PROXY (HTTP/HTTPS proxy URL for all OpenGrok API requests (e.g. http://proxy.company.com:8080). Also set as HTTPS_PROXY.), OPENGROK_RESPONSE_FORMAT_OVERRIDE (Force a specific response format for all tools. Leave unset for per-tool auto-selection (recommended).), OPENGROK_MEMORY_BANK_DIR (Directory where the AI stores investigation notes (active-task.md, investigation-log.md). Defaults to ~/.config/opengrok-mcp/memory-bank/ or workspace-relative when set by the VS Code extension.), OPENGROK_LOCAL_COMPILE_DB_PATHS (Comma-separated paths to compile_commands.json for C/C++ compiler flag and include-path extraction. Leave unset for automatic workspace discovery.), OPENGROK_ENABLE_ELICITATION (Interactive AI Prompts — the AI pauses to ask questions during investigations (project selection, file disambiguation). Requires Claude Code v2.1.76+ or a client that supports MCP Elicitation.), OPENGROK_ENABLE_SAMPLING (AI Sampling — allow the server to request LLM completions for error explanations and summaries. Off by default to avoid consuming premium requests (e.g. GitHub Copilot).), OPENGROK_SAMPLING_MODEL (Model preference for MCP Sampling (used for error explanation and query reformulation).), OPENGROK_ENABLE_FILES_API (Files API Cache — avoids re-uploading unchanged investigation notes. Requires Files API support in the MCP client.), OPENGROK_ENABLE_OBSERVATION_MASKER (Observation Masker — prepend compact history summaries to opengrok_execute results after N turns. Disabled by default; has no benefit for clients that retain full context (Claude Code, Cursor).), OPENGROK_OBSERVATION_MASKER_TURNS (Number of most-recent opengrok_execute results to keep as full text before masking older ones. Default: 10.), OPENGROK_SAMPLING_MAX_TOKENS (Maximum tokens for AI sampling responses (error explanation, query reformulation). Range: 64–4096.), OPENGROK_AUDIT_LOG_FILE (Path to write structured audit events (CSV/JSON). Appends tool invocations, elicitation events, and errors. Leave unset to disable.), OPENGROK_RATELIMIT_RPM (Maximum requests per minute to the OpenGrok server. Default: 60.), OPENGROK_PER_TOOL_RATELIMIT (Per-tool rate limits in requests per minute, as comma-separated tool:rpm pairs (e.g. opengrok_execute:15,opengrok_search_code:30). Overrides OPENGROK_RATELIMIT_RPM for specific tools.), OPENGROK_TIMEOUT (HTTP request timeout in seconds for OpenGrok API calls. Increase for slow servers. Default: 30.), OPENGROK_DEFAULT_MAX_RESULTS (Default maximum number of results returned per search query. Default: 25.), OPENGROK_PASSWORD_FILE (Path to a file containing the OpenGrok password (file-mounted secret for containers). Takes precedence over the OS keychain when OPENGROK_PASSWORD is unset.), OPENGROK_MAX_RESPONSE_BYTES (Hard cap on response payload size in bytes. Overrides the context-budget default. Non-positive values are ignored.), OPENGROK_SEARCH_AND_READ_CAP (Cap for the search_and_read compound tool in bytes. Overrides the context-budget default (2–8 KB depending on tier). Non-positive values are ignored.), OPENGROK_STRICT_SSRF (When true, reject OPENGROK_BASE_URL values pointing at private/loopback IPs at startup. Default: false (warn only; per-request guards still apply).), OPENGROK_JWT_ISSUER (Expected JWT issuer (iss claim) for HTTP transport OAuth. When set, JWTs from other issuers are rejected.), OPENGROK_GRAMMAR_DIR (Directory containing tree-sitter WASM grammars. Overrides the bundled grammar lookup.). The author declared them in the registry entry; get the values from the project itself.