# Memory Leak Debugging

> Diagnoses and resolves memory leaks in JavaScript/Node.js applications. Use when a user reports high memory usage, OOM errors, or wants to analyze heapsnapshots or run memory leak detection tools like memlab.

- **Type:** Skill
- **Install:** `agentstack add skill-calvingit-skills-memory-leak-debugging`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [calvingit](https://agentstack.voostack.com/s/calvingit)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [calvingit](https://github.com/calvingit)
- **Source:** https://github.com/calvingit/skills/tree/main/external-skills/Tool/memory-leak-debugging

## Install

```sh
agentstack add skill-calvingit-skills-memory-leak-debugging
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Memory Leak Debugging

This skill provides expert guidance and workflows for finding, diagnosing, and fixing memory leaks in JavaScript and Node.js applications.

## Core Principles

- **Prefer `memlab`:** Do NOT attempt to read raw `.heapsnapshot` files directly, as they are extremely large and will consume too many tokens. Always recommend and use `memlab` to process snapshots and identify leak traces.
- **Isolate the Leak:** Determine if the leak is in the browser (client-side) or Node.js (server-side).
- **Common Culprits:** Look for detached DOM nodes, unhandled closures, global variables, event listeners not being removed, and caches growing unbounded. _Note: Detached DOM nodes are sometimes intentional caches; always ask the user before nulling them._

## Workflows

### 1. Capturing Snapshots

When investigating a frontend web application memory leak, utilize the `chrome-devtools-mcp` tools to interact with the application and take snapshots.

- Use tools like `click`, `navigate_page`, `fill`, etc., to manipulate the page into the desired state.
- Revert the page back to the original state after interactions to see if memory is released.
- Repeat the same user interactions 10 times to amplify the leak.
- Use `take_heapsnapshot` to save `.heapsnapshot` files to disk at baseline, target (after actions), and final (after reverting actions) states.

### 2. Using Memlab to Find Leaks (Recommended)

Once you have generated `.heapsnapshot` files using `take_heapsnapshot`, use `memlab` to automatically find memory leaks.

- Read [references/memlab.md](references/memlab.md) for how to use `memlab` to analyze the generated heapsnapshots.
- Do **not** read raw `.heapsnapshot` files using `read_file` or `cat`.

### 3. Identifying Common Leaks

When you have found a leak trace (e.g., via `memlab` output), you must identify the root cause in the code.

- Read [references/common-leaks.md](references/common-leaks.md) for examples of common memory leaks and how to fix them.

### 4. Fallback: Comparing Snapshots Manually

If `memlab` is not available, you MUST use the fallback script in the references directory to compare two `.heapsnapshot` files and identify the top growing objects and common leak types.

Run the script using Node.js:

```bash
node skills/memory-leak-debugging/references/compare_snapshots.js  
```

The script will analyze and output the top growing objects by size and highlight the 3 most common types of memory leaks (e.g., Detached DOM nodes, closures, Contexts) if they are present.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [calvingit](https://github.com/calvingit)
- **Source:** [calvingit/skills](https://github.com/calvingit/skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-calvingit-skills-memory-leak-debugging
- Seller: https://agentstack.voostack.com/s/calvingit
- Browse the marketplace: https://agentstack.voostack.com/browse

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