Codegraph MCP

Server: project-0-ui-codegraph / codegraph
Underlying service: Serve · Codegraph

Repository code graph: symbol locations, call chains, blast radius. Runs after P0/P0.5/P1, before broad Grep.

Tools

Tool	Purpose
codegraph_explore	Understand logic/flow/architecture (preferred, usually once)
codegraph_search	Find symbol location (optional kind)
codegraph_callers	Who calls this symbol
codegraph_callees	What this symbol calls
codegraph_impact	Blast radius before changes
codegraph_node	Full implementation (includeCode: true)
codegraph_files	Indexed directory structure
codegraph_status	Index health (on failure only)

When to Trigger

Trigger (any):

• New feature / refactor / API needing call relationships
• Bug needing call-chain tracing
• "Where is this called?" / "What breaks if I change this?"
• User says "use codegraph"

Skip:

• New file with no existing dependencies
• Simple single-file edit (user gave file:line)
• String replace, config change only
• Not initialized (no .codegraph/) → suggest codegraph init -i
• User says "skip codegraph"

Hard Constraints

• Forbidden: Grep + Read same file after explore already returned source
• Forbidden: Loop codegraph_node; use one explore instead
• Only stale files need Read verification
• Do not replace writing files, tests, or lint with codegraph

Examples

What is the call chain for app-center filter logic?

What breaks if I change UserService.login?

Related

• Routing · Code understanding
• Serve · Codegraph