MCP server

grove serve runs an MCP server over stdio (newline-delimited JSON-RPC 2.0), exposing the same seven tools for every registered language. Register it with a coding agent and the agent gains structural sight.

Project-scoped registration for Claude Code lives in .mcp.json (written by grove init):

{ "mcpServers": { "grove": { "command": "…/target/release/grove", "args": ["serve"] } } }

Availability vs. adoption

.mcp.json makes the tools available; a CLAUDE.md steering directive (see VISION §6.4.1) is what gets the agent to actually use them rather than defaulting to grep / whole-file reads. grove init --as mcp writes both — see Setup.

Two surfaces, one at a time

grove isn’t the only MCP server in the family. grove-explore is a separate binary with its own MCP server — a single explore tool that delegates broad “where is X” questions to a local LLM and returns validated file:line citations (see Setup — explore-mode). A project registers one surface or the other, never both (see ADR 0005) — both together would put eight tools in front of the agent with no rule for choosing:

Both surfaces register under the same grove key, so the locator’s tool is mcp__grove__explore — the historical name, and one the outer agent reads as “grove”, not as a binary. Switching modes swaps the entry; grove init strips the surface you left. See Setup for the full --as mcp-llm wiring.

Tool schemas

Every inputSchema is a plain {type: "object", properties, required?}. Tool list is returned by initialize → tools/list. outline is tiered (--detail 0|1|2); symbols/map take name (exact, case-insensitive) plus a nameContains boolean for substring matching.

Result & error model

Tool results are JSON inside an MCP text block. Tool-level failures come back as isError: true with a message so the model can recover (e.g. missing required arg, unknown language, no identifier at a position). Unknown method → -32601 method not found; unknown tool / bad args → -32602 invalid params.

Same engine as the CLI

grove serve and grove <verb> call the same ops library, so a human at the shell and an agent over MCP see identical bytes. The cross-harness skill prefers the MCP tools when the host exposes them and falls back to the CLI otherwise — equal partners over one engine.

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