pi-codegraph-fix

The CodeGraph plugin for pi that actually works.

中文版

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Features

• Switch projects freely — uses ctx.cwd instead of process.cwd(), no more silent tool loss when you change projects
• Zero zombie processes — cleanup on session shutdown, process exit, and SIGTERM/SIGHUP. No more pile-up
• Lazy start — spawns codegraph only when you first use it, doesn't slow down session launch
• Multi-project friendly — each project gets its own MCP client, switches automatically
• No misleading hints — injects CodeGraph instructions only when tools are actually ready

Quick Install

pi install npm:pi-codegraph-fix

You also need CodeGraph CLI (npm install -g @colbymchenry/codegraph) and your project indexed (codegraph init).

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The Problems

1. CodeGraph goes silent when you switch projects

You pi session=<other-project> or launch pi from ~ instead of your project root. Suddenly codegraph tools disappear. No error, just nothing.

Why: The original plugin used process.cwd() to find .codegraph/codegraph.db. That always points to wherever pi was first launched — not your current session's project. Wrong project → no DB → no tools → silent failure.

2. Zombie process pile-up

Every time you close pi, the codegraph serve --mcp subprocess doesn't die. After a few sessions you have a dozen of them fighting over the same socket — causing "server disconnected" errors on every codegraph call.

Real case: 12 zombie processes accumulated over 9 hours across 6 sessions. Every codegraph call spun the roulette wheel on which zombie had the socket lock.

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The Fix

ctx.cwd instead of process.cwd() — reads the current session's working directory from pi, so it works no matter where or how you launched pi.

Three-path cleanup — kills the MCP subprocess on normal exit, crash, or terminal close:

Path	When
session_shutdown	pi exits normally
process.once("exit")	Node process ends
SIGTERM / SIGHUP	Terminal close, kill

No more zombies. No more "server disconnected".

How It Works

1. On session_start, check if ctx.cwd/.codegraph/codegraph.db exists (instant file check)
2. On first codegraph tool call, spawn codegraph serve --mcp in background (lazy, doesn't block session)
3. Discover available tools via MCP tools/list protocol
4. Register all tools with pi.registerTool()
5. Inject usage instructions into system prompt via before_agent_start after tools are ready
6. On session_shutdown or process exit, clean up all MCP clients

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Changes from Upstream

This fork builds on two earlier projects. Both had the same core bug: using process.cwd() breaks when switching projects, and neither cleaned up their child processes properly.

Bug fixes

Bug	Upstream source	Fix in this fork
Tools disappear when switching projects	Both codegraph-pi & pi-codegraph used process.cwd() — always points to pi's launch dir, not the current session	ctx.cwd reads the actual session working directory from pi
Child process not in right directory	Same root cause — codegraph runs in wrong CWD	spawn with explicit cwd: projectRoot
Zombie processes on exit	codegraph-pi had no cleanup at all; pi-codegraph's cleanup was incomplete	Three-path cleanup: session_shutdown, process.once("exit"), SIGTERM/SIGHUP
LLM tries to use codegraph tools when there's no index	codegraph-pi injected system prompt unconditionally	Only inject usage hints after tools are actually ready

Optimizations (new in this fork)

Optimization	Why
Lazy connect	Spawns codegraph on first tool use instead of at session start — faster launch
Smart prompt injection	Waits for tools to register before telling the LLM about them — no misleading hints

Inherited features

Feature	From
Dynamic tool discovery via MCP tools/list	SeanPedersen/pi-codegraph
Multi-project MCP clients (one per CWD)	SeanPedersen/pi-codegraph
Self-contained single file	SeanPedersen/pi-codegraph
before_agent_start system prompt injection	nosuiyi/codegraph-pi
.codegraph/codegraph.db exact check	nosuiyi/codegraph-pi

Credits

• nosuiyi/codegraph-pi — original pi extension
• SeanPedersen/pi-codegraph — multi-client architecture