Official agent skill

Runtime Debug

Debug and verification workflow for runtime-bundle and module-resolution regressions.

OfficialMITAuto-check passedDevelopment

Install Runtime Debug

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/runtime-debug .claude/skills/runtime-debug && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .claude/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/runtime-debug .agents/skills/runtime-debug && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .agents/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/runtime-debug .cursor/skills/runtime-debug && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .cursor/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/vercel/next.js.git --path .agents/skills/runtime-debug

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/runtime-debug .gemini/skills/runtime-debug && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .gemini/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/runtime-debug .github/skills/runtime-debug && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .github/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vercel/next.js --skill runtime-debug -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install vercel/next.js runtime-debug --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/next.js.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/runtime-debug .opencode/skills/runtime-debug && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "runtime-debug" agent skill from https://github.com/vercel/next.js/tree/canary/.agents/skills/runtime-debug into .opencode/skills/runtime-debug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "runtime-debug", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: runtime-debug
GitHub stars: 143k
Used in: 1 other repo
Token cost: ~618 tokens
SKILL.md length: 205 words
Files: 1
Skills in repo: 27
Repo updated: Oct 8, 2026
First seen: Oct 8, 2026
Licence: MIT

At a glance

Debug and verification workflow for runtime-bundle and module-resolution regressions.

Works in 3 steps: Inspect route trace artifacts… → Inspect traced server chunks for… → Add a test-start-webpack assertion that…
Diagnosing unexpected module inclusions
SKILL.md covers Local Repro Discipline, Stack Trace Visibility, User-Bundle Regression Guardrail and Bundle Tracing / Inclusion Proof, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Runtime Debug is an agent skill from vercel/next.js, published by the product's own GitHub organization. Debug and verification workflow for runtime-bundle and module-resolution regressions. Use when diagnosing unexpected module inclusions, bundle size regressions, or CI failures related to NEXTSKIPISOLATE, nft.json traces, or runtime bundle selection (module.compiled.js). Covers CI env mirroring, full stack traces via NEXTSHOWIGNORELISTED, route trace inspection, and webpack stats diffing.

Its SKILL.md is about 620 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development, covering Debugging, Failing and flaky tests and Crypto and DeFi analysis. It works with webpack, Next.js and Turborepo. The licence is MIT.

When your agent uses it

Diagnosing unexpected module inclusions
Bundle size regressions
CI failures related to NEXTSKIPISOLATE
Nft.json traces

Example prompts

“/runtime-debug”

Workflow steps

3 steps, taken from the first numbered list in SKILL.md.

Inspect route trace artifacts (.next/server/.../page.js.nft.json).
Inspect traced server chunks for forbidden internals (e.g. next/dist/server/stream-utils/node-stream-helpers.js, node:stream/promises).
Add a test-start-webpack assertion that reads the route trace and traced server chunks, and fails on forbidden internals. This validates…

What it can do on your machine

Read from SKILL.md and the folder at commit a32ddfd. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Runtime Debug loads about 618 tokens when it runs. Until then it costs about 103 tokens; SKILL.md has 205 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~103
When it runs · the whole SKILL.md, loaded when a task matches: ~618

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from vercel/next.js at commit a32ddfd, republished under its MIT licence (© vercel). 205 words, ~618 tokens.

Download SKILL.mdSave it as .claude/skills/runtime-debug/SKILL.md (or your agent's skills folder).

name: runtime-debug
description: Debug and verification workflow for runtime-bundle and module-resolution regressions. Use when diagnosing unexpected module inclusions, bundle size regressions, or CI failures related to NEXT_SKIP_ISOLATE, nft.json traces, or runtime bundle selection (module.compiled.js). Covers CI env mirroring, full stack traces via __NEXT_SHOW_IGNORE_LISTED, route trace inspection, and webpack stats diffing.
metadata.internal: true

Runtime Debug

Use this skill when reproducing runtime-bundle, module-resolution, or user-bundle inclusion regressions.

Local Repro Discipline

Mirror CI env vars when reproducing CI failures.
Key variables: IS_WEBPACK_TEST=1 forces webpack (turbopack is default), NEXT_SKIP_ISOLATE=1 skips packing next.js.
For module-resolution validation, always rerun without NEXT_SKIP_ISOLATE=1.

Stack Trace Visibility

Set __NEXT_SHOW_IGNORE_LISTED=true to disable the ignore-list filtering in dev server error output. By default, Next.js collapses internal frames to at ignore-listed frames, which hides useful context when debugging framework internals. Defined in packages/next/src/server/patch-error-inspect.ts.

User-Bundle Regression Guardrail

When user next build starts bundling internal Node-only helpers unexpectedly:

Inspect route trace artifacts (.next/server/.../page.js.nft.json).
Inspect traced server chunks for forbidden internals (e.g. next/dist/server/stream-utils/node-stream-helpers.js, node:stream/promises).
Add a test-start-webpack assertion that reads the route trace and traced server chunks, and fails on forbidden internals. This validates user-project bundling (not publish-time runtime bundling).

Bundle Tracing / Inclusion Proof

To prove what user bundling includes, emit webpack stats from the app's next.config.js:

// next.config.js
module.exports = {
  webpack(config) {
    config.profile = true
    return config
  },
}

Then use stats.toJson({ modules: true, chunks: true, reasons: true }) and diff webpack-stats-server.json between modes. This gives concrete inclusion reasons (e.g. which module required node:stream/promises) and is more reliable than analyzer HTML alone.

$flags - flag wiring (config/schema/define-env/runtime env)
$dce-edge - DCE-safe require patterns and edge constraints
$react-vendoring - entry-base boundaries and vendored React

Files

Just SKILL.md in .agents/skills/runtime-debug of vercel/next.js.

Open the folder on GitHubat commit a32ddfd

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in vercel/next.js, which our catalogue first saw on October 8, 2026.

OpenHikmah/openhikmah-web.agents/skills/runtime-debug

Compare with similar skills

Runtime Debug next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Runtime Debug compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Runtime Debug this skillvercel/next.js	143k	1 repos	~618	Automated safety check: Pass	MIT	today
Nextjs Bundle Optimizerpproenca/dot-skills	215	—	~1.5k	Automated safety check: Pass	MIT	1 mo ago
Nextjs Turbopackaffaan-m/ECC	275k	1 repos	~300	Automated safety check: Pass	MIT	3 days ago
Nextjs16 Skillselophanto/EloPhanto	106	—	~1.4k	Automated safety check: Pass	Custom licence	7 days ago
Nextjs Turbopackaffaan-m/ECC	275k	—	~841	Automated safety check: Pass	MIT	3 days ago
Nextjs Turbopackaffaan-m/ECC	275k	—	~364	Automated safety check: Pass	MIT	3 days ago

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Questions about Runtime Debug

What does Runtime Debug do?

Debug and verification workflow for runtime-bundle and module-resolution regressions. js, published by the product's own GitHub organization. Debug and verification workflow for runtime-bundle and module-resolution regressions.

When should I use Runtime Debug?

Runtime Debug fits situations like: diagnosing unexpected module inclusions; bundle size regressions; CI failures related to NEXTSKIPISOLATE; nft.json traces.

How do I install Runtime Debug in Claude Code?

Run `npx skills add vercel/next.js --skill runtime-debug -a claude-code`. Or copy the skill folder (.agents/skills/runtime-debug in vercel/next.js) into .claude/skills/runtime-debug in your project. Claude Code loads it when a task matches its description.

How do I install Runtime Debug in Codex?

Run `npx skills add vercel/next.js --skill runtime-debug -a codex`. Or copy the skill folder (.agents/skills/runtime-debug in vercel/next.js) into .agents/skills/runtime-debug in your project. Codex loads it when a task matches its description.

Can I use Runtime Debug in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add vercel/next.js --skill runtime-debug -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/runtime-debug, .gemini/skills/runtime-debug, .github/skills/runtime-debug and .opencode/skills/runtime-debug in your project.

What does Runtime Debug need to run?

SKILL.md names no scripts, command-line tools or credentials: Runtime Debug is instructions for the agent only.

Does Runtime Debug access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Runtime Debug safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Runtime Debug use?

Runtime Debug is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Runtime Debug use?

About 618 tokens (SKILL.md is roughly 2.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Runtime Debug?

Skills that share tags, products or a category with Runtime Debug: Nextjs Bundle Optimizer (pproenca/dot-skills, 215 stars), Nextjs Turbopack (affaan-m/ECC, 275k stars), Nextjs16 Skills (elophanto/EloPhanto, 106 stars) and Nextjs Turbopack (affaan-m/ECC, 275k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Runtime Debug?

vercel (a GitHub organization, an official publisher) maintains it in vercel/next.js, which has 143,241 GitHub stars. The repository holds 27 skills in this directory. The repository was last updated on October 8, 2026.

Source: vercel/next.js on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Runtime Debug

Install Runtime Debug

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Runtime Debug

Local Repro Discipline

Stack Trace Visibility

User-Bundle Regression Guardrail

Bundle Tracing / Inclusion Proof

Files

Used in 1 other repository

Compare with similar skills

Similar skills

Nextjs Bundle Optimizer

Nextjs Turbopack

Nextjs16 Skills

Nextjs Turbopack

Nextjs Turbopack

Setup Browser SDK Sourcemaps

More from vercel/next.js

Gh Stack

Sandbox Bench

Next Dev Loop

Docs Diagrams

Next Cache Components Adoption

React Sync

Questions about Runtime Debug

Install Runtime Debug

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Runtime Debug

Local Repro Discipline

Stack Trace Visibility

User-Bundle Regression Guardrail

Bundle Tracing / Inclusion Proof

Related Skills

Files

Used in 1 other repository

Compare with similar skills

Similar skills

More from vercel/next.js

Related

Questions about Runtime Debug