yokay-browser-verifier

yokay-browser-verifier is an agent for Claude Code from srstomp/pokayokay. It costs 63 tokens per session (1,248 once invoked), scanned A, original, MIT.

An agent that checks website or application interface changes in a real browser, including visual appearance, interactions, and browser-console errors.

In plain words
What is it for?
Opening the changed interface, testing normal and edge-case interactions, capturing screenshots, checking console errors, and reporting PASS, ISSUE, or SKIP.
Why use it?
It provides evidence that a user interface works beyond what a code review or automated check can show.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the pokayokay plugin — 24 skills, 23 commands, 14 agents, 4 hooks, 1 MCP server shipped together

Good fit Opening the changed interface, testing normal and edge-case interactions, capturing screenshots, checking console errors, and reporting PASS, ISSUE, or SKIP.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/srstomp/pokayokay/yokay-browser-verifier
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.

Clone the repo
git clone --depth 1 https://github.com/srstomp/pokayokay

Made for: Claude Code.

Or install pokayokay, the plugin that ships this one along with the rest of its 24 skills, 23 commands, 14 agents, 4 hooks, 1 MCP server.

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.

agentmods badge for yokay-browser-verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/srstomp/pokayokay/yokay-browser-verifier.svg)](https://agentmods.dev/agents/srstomp/pokayokay/yokay-browser-verifier)
Your own site
<a href="https://agentmods.dev/agents/srstomp/pokayokay/yokay-browser-verifier"><img src="https://agentmods.dev/badge/agents/srstomp/pokayokay/yokay-browser-verifier.svg" alt="Measured on agentmods" height="20"></a>
Per session 63 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,248 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00063 $0.01248
Opus 5 $0.00032 $0.00624
Sonnet 5 $0.00013 $0.00250
Haiku 4.5 $0.00006 $0.00125

Measured 7d ago against content hash 033f9dccfdb4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

yokay-browser-verifier 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 7d 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.

plugins/pokayokay/agents/yokay-browser-verifier.md · 223 lines

How it starts

The opening of the file, as written. The whole thing — 223 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Browser Verification Agent

You verify that UI changes work correctly in a real browser. You receive task details and server information, then perform visual and functional verification.

Behavioral Defaults

  • Default to checking what the user would check. Click buttons, fill forms, test flows.
  • Default to capturing evidence (screenshots) for every finding.
  • Default to checking console for errors even if the UI looks fine.

Critical Rules

  • NEVER skip console error check. Silent JS errors hide real bugs.
  • NEVER PASS without at least one screenshot as evidence.
  • NEVER test only the happy path. Try at least one error/edge case.

Core Principle

NAVIGATE → OBSERVE → VERIFY → REPORT

You are an objective verifier. You check if what was implemented actually works in the browser.

Input You Receive

  • Task title and description
  • Acceptance criteria
  • Files that were changed
  • Server URL and port
  • What the implementer says they built

Verification Process

Step 1: Navigate to Server

browser_navigate to the server URL

If a specific path is relevant to the task (e.g., task added a settings page), navigate there.

Step 2: Capture Initial State

  1. Take a screenshot:

    browser_take_screenshot with appropriate filename
    
  2. Get accessibility snapshot:

    browser_snapshot
    

The snapshot shows all interactive elements and their refs.

Step 3: Define What to Verify

Based on the task, list what should be true:

  • What elements should exist
  • What they should look like
  • What interactions should work

Example:

Task: "Add delete button to each task row" Expected:

  • Each task row has a button
  • Button is labeled "Delete" or has delete icon
  • Button is clickable

Step 4: Verify Visual Elements

Using the snapshot, check each expected element:

  • Is it present?
  • Is it in the right place?
  • Does it have correct attributes?

Step 5: Verify Interactions (if applicable)

If the task involves behavior:

Read the full file on GitHub · 223 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.

  1. 7d ago First seen · 223 lines · 63 tokens per session scan A 033f9dccfdb4

Subscribe to this mod's changes

yokay-browser-verifier is an agent published in the GitHub repository srstomp/pokayokay (9 stars, last pushed 2mo ago), licensed MIT. It adds 63 tokens to every session and 1,248 once invoked, about $0.0003 per session on Opus 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.

Related

Other agents, from other repositories

website-cloner

Pixel-perfect website cloning specialist using Chrome MCP - 5-phase pipeline from screenshot reconnaissance to visual QA, git worktree isolation, parallel builders.

vibeeval/vibecosystem · 31 tokens

08-visual-verify

Open daily HTML schedule in Chrome, screenshot it, and verify layout correctness.

assafkip/kipi-system · 20 tokens

alchemist

Creative technologist who sees the browser as an unexplored physics engine. Consult when building UI that needs to feel alive - scroll-driven reveals, morphing transitions, spatial animation systems, anything where the interaction itself IS the product. Thinks in weight, tension, and breath before thinking in code.…

drobins25/craft · 355 tokens

pwa-specialist

Progressive Web App development, service workers, offline-first architecture, and push notification specialist. Use when building installable web apps, implementing offline functionality, or working with service workers. Trigger phrases: PWA, service worker, Web App Manifest, offline-first, push notification…

travisjneuman/.claude · 76 tokens

browser-extension-developer

Chrome, Firefox, and cross-browser extension development specialist. Manifest V3, service workers, content scripts, and WebExtension APIs. Use when building browser extensions or migrating from MV2 to MV3. Trigger phrases: browser extension, Chrome extension, Firefox addon, Manifest V3, MV3, content script, service…

travisjneuman/.claude · 73 tokens

firefox-extension-dev

Hands-on developer that writes the code and reads MDN live when the bundled references fall short. TRIGGER WHEN: creating, debugging or publishing any Firefox extension, WebExtension or browser add-on, migrating Manifest V2 to V3, or fixing cross-browser compatibility.

acaprino/daodan · 58 tokens