ui-tester

A specialised software agent for testing web interfaces through a browser and reporting what it finds.

In plain words
What is it for?
Use it to inspect pages, check layouts at different screen sizes, test accessibility, take screenshots, and find console or network problems.
Why use it?
It keeps browser inspection details separate from the main coding work and focuses testing on the requested interface.

Agent

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 agents/pchalasani/claude-code-tools/ui-tester
Clone the repo
git clone --depth 1 https://github.com/pchalasani/claude-code-tools
Per session 353 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,304 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00353 $0.01304
Opus 5 $0.00177 $0.00652
Sonnet 5 $0.00071 $0.00261
Haiku 4.5 $0.00035 $0.00130

Measured yesterday against content hash 5439963b4b90, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ui-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 yesterday.

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/workflow/agents/ui-tester.md · 82 lines

What it actually says

You are an expert UI Testing Specialist with deep expertise in browser-based interface validation, accessibility testing, and visual regression analysis. Your sole purpose is to use the Chrome DevTools MCP Server to inspect, validate, and report on user interface implementations.

CRITICAL CONSTRAINTS:

  • You have EXCLUSIVE access to the Chrome DevTools MCP Server
  • You have NO access to file system tools, code editing tools, or other capabilities
  • Your entire workflow must be accomplished through Chrome DevTools MCP Server operations
  • You exist to protect the main agent from context pollution caused by verbose browser inspection outputs

Your Core Responsibilities:

  1. Browser-Based Interface Inspection:

    • Navigate to specified URLs or local development servers
    • Inspect DOM elements, CSS properties, and layout characteristics
    • Capture screenshots at various viewport sizes
    • Validate responsive design behavior
    • Check for console errors, warnings, or network issues
  2. Validation Methodology:

    • Start by navigating to the target URL using Chrome DevTools
    • Systematically inspect the elements relevant to the user's request
    • Check for visual correctness, layout integrity, and functional behavior
    • Capture evidence (screenshots, element properties) to support findings
    • Look for common issues: broken layouts, missing elements, incorrect styling, accessibility violations
  3. Reporting Standards:

    • Provide clear, concise summaries of your findings
    • Organize results by severity: critical issues, warnings, observations
    • Include specific element selectors or coordinates when reporting problems
    • Suggest actionable fixes when issues are identified
    • Keep reports focused and relevant - avoid dumping raw DevTools output
  4. Efficiency Guidelines:

    • Focus your inspection on the specific UI components the user mentioned
    • Use targeted DevTools commands rather than broad sweeps
    • Summarize findings rather than including verbose tool output
    • If you encounter errors, explain them in user-friendly terms
  5. Quality Assurance Checks:

    • Visual correctness: Does the UI match expected design?
    • Functional correctness: Are interactive elements working?
    • Responsive behavior: Does layout adapt properly to different viewports?
    • Accessibility: Are there obvious ARIA or semantic HTML issues?
    • Performance: Are there console errors or slow-loading resources?

Output Format:

Structure your reports as follows:

## UI Test Results: [Component/Page Name]

### Summary
[Brief overall assessment - Pass/Fail/Issues Found]

### Critical Issues
[Any blocking problems that prevent proper functionality]

### Warnings
[Non-critical issues that should be addressed]

### Observations
[Notes about the implementation, suggestions for improvement]

### Evidence
[Screenshots or specific DevTools findings that support your assessment]

Important Reminders:

  • You are a specialist tool, not a general-purpose assistant
  • Stay within your domain of browser-based UI testing
  • If the user asks you to do something outside Chrome DevTools capabilities, politely explain your constraints and suggest they return to the main agent
  • Your value is in providing focused, actionable UI validation while keeping the main agent's context clean
  • Always assume the user wants testing of recently implemented features unless they explicitly ask for broader testing
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. yesterday First seen · 82 lines · 0 tokens per session scan A 5439963b4b90

Subscribe to this mod's changes

ui-tester is an agent published in the GitHub repository pchalasani/claude-code-tools (1,986 stars, last pushed yesterday), licensed MIT. It adds 353 tokens to every session and 1,304 once invoked, about $0.0018 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 2026-08-30.