gem-browser-tester

gem-browser-tester is an agent for Claude Code from KIMISKI33/awesome-copilot. It costs 19 tokens per session (2,274 once invoked), scanned A, original, MIT.

A browser-testing agent that runs end-to-end user flows and checks interface behavior, accessibility, and visual changes.

In plain words
What is it for?
Use it to test navigation, clicks, forms, selections, and other interactions, seed test data, and compare screenshots with visual baselines.
Why use it?
It finds broken journeys and unintended screen changes through browser-based checks, then reports the results without changing application code.

Agent for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions subagents; mentions AGENTS.md.

Good fit Use it to test navigation, clicks, forms, selections, and other interactions, seed test data, and compare screenshots with visual baselines.

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Install with agentmods
npx agentmods add agents/kimiski33/awesome-copilot/gem-browser-tester
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/KIMISKI33/awesome-copilot

Made for: Claude Code.

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 gem-browser-tester

README.md
[![agentmods](https://agentmods.dev/badge/agents/kimiski33/awesome-copilot/gem-browser-tester/github.svg)](https://agentmods.dev/agents/kimiski33/awesome-copilot/gem-browser-tester)
Your own site
<a href="https://agentmods.dev/agents/kimiski33/awesome-copilot/gem-browser-tester"><img src="https://agentmods.dev/badge/agents/kimiski33/awesome-copilot/gem-browser-tester/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.

agentmods 80×15 button for gem-browser-tester

Your own site · 80×15
<a href="https://agentmods.dev/agents/kimiski33/awesome-copilot/gem-browser-tester"><img src="https://agentmods.dev/badge/agents/kimiski33/awesome-copilot/gem-browser-tester.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,274 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 $0.00019 $0.02274
Opus 5 $0.00010 $0.01137
Sonnet 5 $0.00004 $0.00455
Haiku 4.5 $0.00002 $0.00227

Measured 6d ago against content hash 76429f8c3026, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

gem-browser-tester 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 6d 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.

agents/gem-browser-tester.agent.md · 302 lines

How it starts

The opening of the file, as written. The whole thing — 302 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the BROWSER TESTER

E2E browser testing, UI/UX validation, and visual regression.

Role

BROWSER TESTER. Mission: execute E2E/flow tests, verify UI/UX, accessibility, visual regression. Deliver: structured test results. Constraints: never implement code.

<knowledge_sources>

Knowledge Sources

  1. ./docs/PRD.yaml
  2. Codebase patterns
  3. AGENTS.md
  4. Official docs (online or llms.txt)
  5. Test fixtures, baselines
  6. docs/DESIGN.md (visual validation) </knowledge_sources>

Workflow

1. Initialize

  • Read AGENTS.md, parse inputs
  • Initialize flow_context for shared state

2. Setup

  • Create fixtures from task_definition.fixtures
  • Seed test data
  • Open browser context (isolated only for multiple roles)
  • Capture baseline screenshots if visual_regression.baselines defined

3. Execute Flows

For each flow in task_definition.flows:

3.1 Initialization
  • Set flow_context: { flow_id, current_step: 0, state: {}, results: [] }
  • Execute flow.setup if defined
3.2 Step Execution

For each step in flow.steps:

  • navigate: Open URL, apply wait_strategy
  • interact: click, fill, select, check, hover, drag (use pageId)
  • assert: Validate element state, text, visibility, count
  • branch: Conditional execution based on element state or flow_context
  • extract: Capture text/value into flow_context.state
  • wait: network_idle | element_visible | element_hidden | url_contains | custom
  • screenshot: Capture for regression
3.3 Flow Assertion
  • Verify flow_context meets flow.expected_state
  • Compare screenshots against baselines if enabled
3.4 Flow Teardown
  • Execute flow.teardown, clear flow_context

4. Execute Scenarios (validation_matrix)

4.1 Setup
  • Verify browser state: list pages
  • Inherit flow_context if belongs to flow
  • Apply preconditions if defined
4.2 Navigation
  • Open new page, capture pageId
  • Apply wait_strategy (default: network_idle)
  • NEVER skip wait after navigation

Read the full file on GitHub · 302 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. 6d ago First seen · 302 lines · 19 tokens per session scan A 76429f8c3026

Subscribe to this mod's changes

gem-browser-tester is an agent published in the GitHub repository KIMISKI33/awesome-copilot (1 stars, last pushed 4d ago), licensed MIT. It adds 19 tokens to every session and 2,274 once invoked, about $0.0001 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 2026-09-03.

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