MCP Server

CodeGraph runs as a Model Context Protocol server. Start it with:

codegraph serve --mcp

Agents configured by the installer launch this automatically. When a .codegraph/ index exists, the agent uses the tools below.

Tools

Tool	Purpose
codegraph_search	Find symbols by name across the codebase
codegraph_context	Build relevant code context for a task — composes search + node + callers + callees in one call
codegraph_trace	Trace the call path between two symbols (“how does X reach Y”) in one call — each hop with its body inline, following dynamic-dispatch hops (callbacks, React re-render, interface→impl) that grep can’t
codegraph_callers	Find what calls a function
codegraph_callees	Find what a function calls
codegraph_impact	Analyze what code is affected by changing a symbol
codegraph_node	Get details about a specific symbol (optionally with source code)
codegraph_explore	Return source for several related symbols grouped by file, plus a relationship map, in one call
codegraph_files	Get the indexed file structure (faster than filesystem scanning)
codegraph_status	Check index health and statistics

How agents should use it

CodeGraph is the pre-built search index. For “how does X work?”, architecture, trace, or where-is-X questions, an agent should answer in a handful of CodeGraph calls and stop — typically with zero file reads — rather than re-deriving the answer with grep + Read. A direct CodeGraph answer is a handful of calls; a grep/read exploration is dozens.

The installer writes this guidance into each agent’s instructions file automatically.