NxtSoftLabs
CGRAPH DOCS — CONTENTS
CGRAPH

MCP Integration

cgraph-mcp exposes the graph to coding agents over the Model Context Protocol (MCP). Its tool calls route through the same daemon operation handler as the thin client, so an agent gets exactly the semantics the CLI does.

The protocol

cgraph-mcp speaks newline-delimited JSON-RPC 2.0 over stdio, protocol version 2024-11-05. It implements the standard handshake and tool methods:

JSON-RPC 2.0 over stdio (protocol 2024-11-05)
MethodPurpose
initializeHandshake and capability exchange.
notifications/initializedClient signals it's ready.
tools/listEnumerate the available tools.
tools/callInvoke a tool.

Invalid JSON receives a JSON-RPC parse error response rather than crashing the server.

The request flow

agent ── JSON-RPC (stdio) ──> cgraph-mcp ──> daemon operation handler ──> graph
  ^                                                                        |
  └──────────────────── JSON result ──────────────────────────────────────┘
An agent's tool call, end to end

The eight tools

graph_query
Find nodes matching a query.
graph_explain
Explain a node and its role.
graph_impact
The transitive blast radius of a change.
graph_path
The shortest path between two symbols.
graph_context
A packed, budgeted neighborhood for the agent.
graph_update
Fold in changes / trigger a rescan.
graph_status
Daemon and graph health.
graph_shutdown
Stop the daemon.

How it finds the project and the daemon

cgraph-mcp resolves the project root in priority order:

--root flag  >  CLAUDE_PROJECT_DIR env var  >  working directory

and discovers the daemon in priority order:

--daemon <path>  >  CGRAPH_DAEMON_PATH env var  >  graphd next to the binary  >  build-tree layout

This is why cgraph-mcp works from an agent with minimal configuration: an agent that sets CLAUDE_PROJECT_DIR (like Claude Code) and ships graphd next to the binary needs no flags at all.

Where to go next

← PREVIOUS
Internals
NEXT →
AI Agent Integration