What is chrome-verify-checks?

A verification workflow for browser extensions, which are programs that add features to web browsers.

Use it to verify a Chrome extension after changes by running its build, checking the service worker and manifest, testing each target website, tracing messages, running tests, and following the manual-load checklist.

It checks more than whether the extension builds: it also checks its background process, permissions, page scripts, messages, and loading behavior.

chrome-verify-checks — Skill for Claude Code by jhlee0409

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.

Any agent

npx skills add jhlee0409/omni-harness-kit --skill chrome-verify-checks

Clone the repo

git clone --depth 1 https://github.com/jhlee0409/omni-harness-kit

Made for: Claude Code.

Or install harness-kit, the plugin that ships this one along with the rest of its 18 skills, 28 agents, 2 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/jhlee0409/omni-harness-kit/chrome-verify-checks/github.svg)](https://agentmods.dev/skills/jhlee0409/omni-harness-kit/chrome-verify-checks)

Your own site

<a href="https://agentmods.dev/skills/jhlee0409/omni-harness-kit/chrome-verify-checks"><img src="https://agentmods.dev/badge/skills/jhlee0409/omni-harness-kit/chrome-verify-checks/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/jhlee0409/omni-harness-kit/chrome-verify-checks"><img src="https://agentmods.dev/badge/skills/jhlee0409/omni-harness-kit/chrome-verify-checks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 126 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,206 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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 5.1	$0.00126	$0.01206
Opus 5.5	$0.00050	$0.00482
Sonnet 5.5	$0.00025	$0.00241
Haiku 4.5	$0.00013	$0.00121

Measured 2mo ago against content hash 14ad0add2fe8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

chrome-verify-checks 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 2mo 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.

adapters/omp/skills/chrome-verify-checks/SKILL.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Chrome extension verification — 7 checks + manual-load checklist

chrome-extension/ is a strong-guard sub-context — a frontend maintainer cannot easily catch MV3 service-worker quirks or per-site content-script breakage. This skill is the canonical verification: prove or disprove that the extension still loads, still talks across its boundaries, and still works on each target site — with real evidence.

You are a fresh-context critic when you load this: you did NOT make the change and you do NOT assume it works. Falsify.

Setup

From git diff --name-only, confirm the change is in chrome-extension/.
Read the sub-context's own guide (TDD entry) and the manifest chrome-extension/manifest.json for the current permissions / matches / background entry.
Read chrome-extension/shared/ for the message-passing protocol shape.

The 7 checks (run every one — do not skip)

Build the extension — cd chrome-extension && npm run build:dev. Capture build output. Any error / warning = finding.
Service Worker compat (vm.createContext) — there is no dedicated sw-compat script in this repo. Inspect the SW entry from chrome-extension/manifest.json background.service_worker, then grep the entry file + its transitive imports for DOM-tied refs (window., document., XMLHttpRequest, localStorage) and for modules known to break under MV3 SW (axios with default adapter, any node:* import, anything pulling in jsdom). Any DOM-tied ref in the SW transitive closure = blocking finding. A ReferenceError: window is not defined at SW boot (visible from chrome://extensions on manual load) is the runtime symptom.
Manifest sanity — verify manifest_version: 3, background.service_worker path resolves to a real built file in dist/, every host_permissions entry is actually used by code (grep), every matches URL pattern resolves to an existing content-script file.
Per-site content-script DOM contract — for each target site the extension supports, grep the selector strings the content script depends on. If a selector is missing in the live DOM, the script silently no-ops on that site. List each selector + the file:line that owns it + the last-verified date if recorded. If a selector cannot be verified, flag it as CANT-VERIFY — manual browser load required by the maintainer.

Read the full file on GitHub · 54 lines

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.

2mo ago First seen · 54 lines · 126 tokens per session scan A 14ad0add2fe8

Subscribe to this mod's changes

chrome-verify-checks is a skill published in the GitHub repository jhlee0409/omni-harness-kit (2 stars, last pushed 3mo ago), licensed MIT. It adds 126 tokens to every session and 1,206 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Browser automation Claude Code E2E testing Testing ai-agents anthropic claude claude-code-plugin cli

chrome-verify-checks

Getting it into your agent

Wrote this? Show the measurements

What it costs to keep this loaded

Grade A, and why

Nothing flagged

How it starts

Chrome extension verification — 7 checks + manual-load checklist

Setup

The 7 checks (run every one — do not skip)

What this file has done since we first saw it

Other skills, from other repositories

proof-e2e

e2e-panther-playwright

playwright-qa

qa-targets

browser-qa

agent-browser