What is memory-leak-debugging?

A guide for finding and fixing memory leaks in JavaScript and Node.js applications. A memory leak happens when a program keeps data it no longer needs, causing memory use to grow and possibly leading to an out-of-memory crash.

Use it with Chrome DevTools memory tools to capture and compare heap snapshots, inspect retained objects, and investigate causes such as detached page elements, event listeners, closures, globals, or unbounded caches.

It provides a structured way to determine whether the leak is in the browser or the Node.js server and to compare memory over time. This is more reliable than guessing from high memory usage alone.

memory-leak-debugging — Skill by ChromeDevTools

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add skills/chromedevtools/chrome-devtools-mcp/memory-leak-debugging

Any agent

npx skills add ChromeDevTools/chrome-devtools-mcp --skill memory-leak-debugging

Clone the repo

git clone --depth 1 https://github.com/ChromeDevTools/chrome-devtools-mcp

Made for: Claude Code, Codex.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 933 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. Scan, not verified.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.00052	$0.00933
Opus 5	$0.00026	$0.00466
Sonnet 5	$0.00010	$0.00187
Haiku 4.5	$0.00005	$0.00093

Measured 3d ago against content hash 895127ac55a3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

memory-leak-debugging scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Reads MCP configurationmediumAgent snooping

mcp.json carries server URLs and auth tokens; reading it lets a mod discover and abuse other integrations.

Advanced memory debugging tools (`compare_heapsnapshots`, `get_heapsnapshot_details`, etc.) are only available when the server is started with the `--memoryDebugging` flag. First check if these tools are available; if no

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

memory-leak-debugging — 100% identical, 0 lines differ
memory-leak-debugging — 86% identical, 8 lines differ

skills/memory-leak-debugging/SKILL.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Memory Leak Debugging

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

Prerequisites

Advanced memory debugging tools (compare_heapsnapshots, get_heapsnapshot_details, etc.) are only available when the server is started with the --memoryDebugging flag. First check if these tools are available; if not, try to read the MCP configuration file to check if --memoryDebugging is enabled.

Core Principles

Prefer MCP memory tools: Do NOT attempt to read raw .heapsnapshot files directly, as they are extremely large and will consume too many tokens. Use the Chrome DevTools MCP heap snapshot tools to summarize, compare, and inspect snapshots.
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.
Close Loaded Snapshots: Heap snapshots can be large. After completing an investigation, use close_heapsnapshot for each loaded snapshot to release memory held by the MCP server.

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 page-scoped tools like click, navigate_page, fill, etc. (specifying pageId) 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 (with pageId) to save .heapsnapshot files to disk at baseline, target (after actions), and final (after reverting actions) states.

2. Comparing Snapshots

Read the full file on GitHub · 59 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

references/common-leaks.md 1.8 KB

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

3d ago First seen · 59 lines · 52 tokens per session scan B 895127ac55a3

Subscribe to this mod's changes

memory-leak-debugging is a skill published in the GitHub repository ChromeDevTools/chrome-devtools-mcp (50,411 stars, last pushed today), licensed Apache-2.0. It adds 52 tokens to every session and 933 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (reads mcp configuration). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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