OpenGrok MCP Server runs on your own machine — the client starts it, so there is no endpoint to ping. 167 installs a week from npm. Last commit 16 Sep 2026.
MCP server bridging OpenGrok search engine with AI for instant context across massive codebases.
What the code does
We read the source, 4 d ago · rules 995398eba69f
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);
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
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 -e 'OPENGROK_BASE_URL=<OPENGROK_BASE_URL>' -- npx -y opengrok-mcp-server{
"mcpServers": {
"opengrok-mcp-server": {
"command": "npx",
"args": [
"-y",
"opengrok-mcp-server"
],
"env": {
"OPENGROK_BASE_URL": "<OPENGROK_BASE_URL>"
}
}
}
}[mcp_servers.opengrok-mcp-server]
command = "npx"
args = ["-y", "opengrok-mcp-server"]
env = { OPENGROK_BASE_URL = "<OPENGROK_BASE_URL>" }{
"mcpServers": {
"opengrok-mcp-server": {
"command": "npx",
"args": [
"-y",
"opengrok-mcp-server"
],
"env": {
"OPENGROK_BASE_URL": "<OPENGROK_BASE_URL>"
}
}
}
}{
"servers": {
"opengrok-mcp-server": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"opengrok-mcp-server"
],
"env": {
"OPENGROK_BASE_URL": "<OPENGROK_BASE_URL>"
}
}
}
}Put your own value in place of
<OPENGROK_BASE_URL> (OpenGrok server base URL (e.g. https://opengrok.example.com/source/)).
The author’s registry entry marks it as required.
Optional settings from the registry entry, left out of the block above:
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).
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OpenGrok MCP Server — questions
Answers built from our own checks of this server.