What is memory-leak-debugging?

A troubleshooting guide for finding memory leaks in JavaScript and Node.js applications. A memory leak occurs when a program keeps data it no longer needs, causing memory use to grow and possibly making the application run out of memory.

Use it to investigate high memory use, out-of-memory errors, detached page elements, lingering event listeners, retained closures, global data, or unbounded caches.

It provides a process for distinguishing browser-side problems from Node.js problems and examining heap snapshots without loading huge raw files directly.

memory-leak-debugging — Skill by operasoftware

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/operasoftware/opera-devtools-mcp/memory-leak-debugging

Any agent

npx skills add operasoftware/opera-devtools-mcp --skill memory-leak-debugging

Clone the repo

git clone --depth 1 https://github.com/operasoftware/opera-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 844 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin 86% copy Near-identical to another mod 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	$0.00844
Opus 5	$0.00026	$0.00422
Sonnet 5	$0.00010	$0.00169
Haiku 4.5	$0.00005	$0.00084

Measured 2d ago against content hash a8e7c7c2cddc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

memory-leak-debugging scanned grade A with 0 findings 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 2d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

86% identical to memory-leak-debugging — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/memory-leak-debugging/SKILL.md · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 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.

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 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. Comparing Snapshots

Once you have generated .heapsnapshot files using take_heapsnapshot, compare them with Chrome DevTools MCP memory tools.

Start with get_heapsnapshot_summary for each snapshot to confirm that the files load and to compare high-level totals.
Use compare_heapsnapshots to compare baseline and target snapshots. Start without classIndex for the summary diff, then request detailed class diffs only for suspicious growth by specifying classIndex.
Use the summary output from compare_heapsnapshots before drilling into specific node IDs.

Read the full file on GitHub · 55 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.

2d ago First seen · 55 lines · 52 tokens per session scan A a8e7c7c2cddc

Subscribe to this mod's changes

memory-leak-debugging is a skill published in the GitHub repository operasoftware/opera-devtools-mcp (8 stars, last pushed 3d ago), licensed Apache-2.0. It adds 52 tokens to every session and 844 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to memory-leak-debugging, differing in 8 lines, and is treated as a copy.

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