OpenGrok MCP Server MCP Server

io.github.IcyHot09/opengrok-mcp-server

Repository Registry

What is the OpenGrok MCP Server MCP server?

MCP server bridging OpenGrok search engine with AI for instant context across massive codebases.

How to install OpenGrok MCP Server

Copy-paste configuration for popular MCP clients.

transport: stdio

Config generated by PluginBench — verify against the source before use.

Environment / auth

OPENGROK_BASE_URL
required
OpenGrok server base URL (e.g. https://opengrok.example.com/source/)
OPENGROK_USERNAME
OpenGrok authentication username. Leave unset for anonymous access.
OPENGROK_PASSWORD
secret
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.

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "opengrok-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "opengrok-mcp-server"
      ],
      "env": {
        "OPENGROK_BASE_URL": "<YOUR_OPENGROK_BASE_URL>",
        "OPENGROK_USERNAME": "<YOUR_OPENGROK_USERNAME>",
        "OPENGROK_PASSWORD": "<YOUR_OPENGROK_PASSWORD>",
        "OPENGROK_VERIFY_SSL": "<YOUR_OPENGROK_VERIFY_SSL>",
        "OPENGROK_CODE_MODE": "<YOUR_OPENGROK_CODE_MODE>",
        "OPENGROK_ENABLE_MEMORY_TOOLS": "<YOUR_OPENGROK_ENABLE_MEMORY_TOOLS>",
        "OPENGROK_DEFAULT_PROJECT": "<YOUR_OPENGROK_DEFAULT_PROJECT>",
        "OPENGROK_CONTEXT_BUDGET": "<YOUR_OPENGROK_CONTEXT_BUDGET>",
        "OPENGROK_API_VERSION": "<YOUR_OPENGROK_API_VERSION>",
        "HTTP_PROXY": "<YOUR_HTTP_PROXY>",
        "OPENGROK_RESPONSE_FORMAT_OVERRIDE": "<YOUR_OPENGROK_RESPONSE_FORMAT_OVERRIDE>",
        "OPENGROK_MEMORY_BANK_DIR": "<YOUR_OPENGROK_MEMORY_BANK_DIR>",
        "OPENGROK_LOCAL_COMPILE_DB_PATHS": "<YOUR_OPENGROK_LOCAL_COMPILE_DB_PATHS>",
        "OPENGROK_ENABLE_ELICITATION": "<YOUR_OPENGROK_ENABLE_ELICITATION>",
        "OPENGROK_ENABLE_SAMPLING": "<YOUR_OPENGROK_ENABLE_SAMPLING>",
        "OPENGROK_SAMPLING_MODEL": "<YOUR_OPENGROK_SAMPLING_MODEL>",
        "OPENGROK_ENABLE_FILES_API": "<YOUR_OPENGROK_ENABLE_FILES_API>",
        "OPENGROK_ENABLE_OBSERVATION_MASKER": "<YOUR_OPENGROK_ENABLE_OBSERVATION_MASKER>",
        "OPENGROK_OBSERVATION_MASKER_TURNS": "<YOUR_OPENGROK_OBSERVATION_MASKER_TURNS>",
        "OPENGROK_SAMPLING_MAX_TOKENS": "<YOUR_OPENGROK_SAMPLING_MAX_TOKENS>",
        "OPENGROK_AUDIT_LOG_FILE": "<YOUR_OPENGROK_AUDIT_LOG_FILE>",
        "OPENGROK_RATELIMIT_RPM": "<YOUR_OPENGROK_RATELIMIT_RPM>",
        "OPENGROK_PER_TOOL_RATELIMIT": "<YOUR_OPENGROK_PER_TOOL_RATELIMIT>",
        "OPENGROK_TIMEOUT": "<YOUR_OPENGROK_TIMEOUT>",
        "OPENGROK_DEFAULT_MAX_RESULTS": "<YOUR_OPENGROK_DEFAULT_MAX_RESULTS>",
        "OPENGROK_PASSWORD_FILE": "<YOUR_OPENGROK_PASSWORD_FILE>",
        "OPENGROK_MAX_RESPONSE_BYTES": "<YOUR_OPENGROK_MAX_RESPONSE_BYTES>",
        "OPENGROK_SEARCH_AND_READ_CAP": "<YOUR_OPENGROK_SEARCH_AND_READ_CAP>",
        "OPENGROK_STRICT_SSRF": "<YOUR_OPENGROK_STRICT_SSRF>",
        "OPENGROK_JWT_ISSUER": "<YOUR_OPENGROK_JWT_ISSUER>",
        "OPENGROK_GRAMMAR_DIR": "<YOUR_OPENGROK_GRAMMAR_DIR>"
      }
    }
  }
}

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