# Memory Leak Debug

Diagnose memory leaks in the Qwen Code CLI using heap snapshots and the chrome-devtools...

- Repository: https://github.com/QwenLM/qwen-code (28858 stars)
- Category: Marketing
- License: Apache-2.0
- Last updated: 2026-11-01
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add QwenLM/qwen-code --skill memory-leak-debug -g -a claude-code -y`
Codex: `npx skills add QwenLM/qwen-code --skill memory-leak-debug -g -a codex -y`
Cursor: `npx skills add QwenLM/qwen-code --skill memory-leak-debug -g -a cursor -y`
Gemini CLI: `npx skills add QwenLM/qwen-code --skill memory-leak-debug -g -a gemini-cli -y`

## Description

Diagnose memory leaks in the Qwen Code CLI using heap snapshots and the chrome-devtools CLI. Use when investigating high memory usage, unbounded growth, or suspected object retention issues.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Memory Leak Debugging

Diagnose memory leaks in the Qwen Code Node.js CLI by capturing heap snapshots
and analyzing retained object sizes via `chrome-devtools` CLI tooling.

## Prerequisites

- `chrome-devtools` CLI (from `chrome-devtools-mcp` package). If not found,
  install with: `npm i chrome-devtools-mcp@latest -g` after user confirmation.
  See https://github.com/ChromeDevTools/chrome-devtools-mcp/blob/main/docs/cli.md
- Node.js 22+ (for `--heapsnapshot-signal` support)

## Step 1: Start the CLI with Snapshot Signal

Use tmux so you can interact with the TUI and trigger snapshots from another
pane. Use the tmux-real-user-testing helper script:

```bash
HELPER=.qwen/skills/tmux-real-user-testing/scripts/tmux-real-user-log.sh
eval "$(bash "$HELPER" start memleak . \
  env QWEN_CODE_NO_RELAUNCH=true NODE_OPTIONS=--heapsnapshot-signal=SIGUSR2 \
  npm run dev)"
echo "SESSION=$SESSION OUTDIR=$OUTDIR"
```

The `eval` exports `SESSION` and `OUTDIR`. Note: shell environment does not
persist across separate tool calls, save the session name from the output and
use it explicitly in subsequent commands.

Notes:

- `npm run dev` runs from TypeScript source via tsx, no build step needed and
  changes to core/cli are reflected immediately.
- `QWEN_CODE_NO_RELAUNCH=true` prevents the CLI from spawning a child process,
  so PID management is simpler.
- `NODE_OPTIONS` propagates the flag through npm → tsx → node.

Get the PID of the actual node process. With `npm run dev`, there's a process
chain (npm → node scripts/dev.js → tsx → node CLI), so walk the tree to the
innermost node child:

```bash
NODE_PID=$(bash .qwen/skills/memory-leak-debug/scripts/find-leaf-node.sh "<session-name>")
```

To profile the production bundle instead (e.g., verifying tree-shaking):
`npm run bundle` first, then use
`env QWEN_CODE_NO_RELAUNCH=true node --heapsnapshot-signal=SIGUSR2 dist/cli.js`
as the command. Since node is the direct pane process, PID discovery is simpler:

The rest: https://github.com/QwenLM/qwen-code/blob/HEAD/.qwen/skills/memory-leak-debug/SKILL.md