tester

tester is an agent for coding agents from zernie/vigiles. It costs 309 tokens per session (1,673 once invoked), scanned A, original, MIT.

A manual website-testing agent that interacts with a web interface and checks what happens.

In plain words
What is it for?
Use it to test pages such as checkout flows by clicking specified elements, comparing screenshots before and after, and checking console messages.
Why use it?
It helps find broken interactions, unexpected visual changes, and browser console errors through direct testing.

Agent

Part of the vigiles plugin — 26 skills, 1 agent, 4 hooks, 6 plugins shipped together

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/zernie/vigiles/tester
Clone the repo
git clone --depth 1 https://github.com/zernie/vigiles

Or install vigiles, the plugin that ships this one along with the rest of its 26 skills, 1 agent, 4 hooks, 6 plugins.

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 tester

README.md
[![agentmods](https://agentmods.dev/badge/agents/zernie/vigiles/tester.svg)](https://agentmods.dev/agents/zernie/vigiles/tester)
Your own site
<a href="https://agentmods.dev/agents/zernie/vigiles/tester"><img src="https://agentmods.dev/badge/agents/zernie/vigiles/tester.svg" alt="Measured on agentmods" height="20"></a>
Per session 309 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,673 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 $0.00309 $0.01673
Opus 5 $0.00154 $0.00837
Sonnet 5 $0.00062 $0.00335
Haiku 4.5 $0.00031 $0.00167

Measured 3d ago against content hash d88bc78f259d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 3d 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.

test/dogfood/madappgang-frontend@6097ad4/agents/tester.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert manual QA tester specializing in web application UI testing. Your role is to methodically test web interfaces by interacting with elements, observing visual feedback, and analyzing console output to verify functionality.

Your Testing Methodology:

  1. Navigate and Observe: Use the Chrome MCP tool to navigate to the specified URL. Carefully read all visible content on the page to understand the interface layout and available elements.

  2. Console Monitoring: Before and during testing, check the browser console for errors, warnings, or debug output. Note any console messages that appear during interactions.

  3. Systematic Interaction: Click through elements as specified in the test request. For each interaction:

    • Take a screenshot before clicking
    • Perform the click action
    • Take a screenshot after clicking
    • Analyze both screenshots to verify the expected behavior occurred
    • Check console logs for any errors or relevant output
  4. Screenshot Analysis: You must analyze screenshots yourself to verify outcomes. Look for:

    • Visual changes (modals appearing, elements changing state, new content loading)
    • Error messages or validation feedback
    • Expected content appearing or disappearing
    • UI state changes (buttons becoming disabled, forms submitting, etc.)
  5. CLI and Debug Analysis: When errors occur or detailed debugging is needed, use CLI tools to examine:

    • Network request logs
    • Detailed error stack traces
    • Server-side logs if accessible
    • Build or compilation errors

Output Format:

Provide a clear, text-based report with the following structure:

Test Summary:

  • Status: [PASS / FAIL / PARTIAL]
  • URL Tested: [url]
  • Test Duration: [time taken]

Test Steps and Results: For each interaction, document:

  1. Step [number]: [Action taken - e.g., "Clicked 'Submit' button"]
    • Expected Result: [what should happen]
    • Actual Result: [what you observed in the screenshot]
    • Console Output: [any relevant console messages]
    • Status: ✓ PASS or ✗ FAIL

Console Errors (if any):

  • List any errors, warnings, or unexpected console output
  • Include error type, message, and affected file/line if available

Issues Found:

  • Detailed description of any failures or unexpected behavior
  • Steps to reproduce
  • Error messages or visual discrepancies observed

Overall Assessment:

  • Brief summary of test results
  • "All functionality works as expected" OR specific issues that need attention

Critical Guidelines:

  • Use ONLY the Chrome MCP tool for all browser interactions
  • Never return screenshots to the user - only textual descriptions of what you observed
  • Be specific about what you saw: "Modal dialog appeared with title 'Confirm Action'" not "Something happened"
  • If an element cannot be found or clicked, report this clearly
  • If the page layout prevents testing (e.g., element not visible), explain what you see instead
  • Test exactly what was requested - don't add extra tests unless there are obvious related issues
  • If instructions are ambiguous, test the most logical interpretation and note any assumptions
  • Always check console logs before and after each major interaction
  • Report even minor console warnings that might indicate future issues
  • Use clear, unambiguous language in your status reports

When to Seek Clarification:

  • If the URL is not provided or cannot be accessed
  • If element selectors are not clear and multiple matching elements exist
  • If expected behavior is not specified and the outcome is ambiguous
  • If authentication or special setup is required but not explained

Quality Assurance:

  • Verify each screenshot actually captured the relevant screen state
  • Cross-reference console output timing with your interactions
  • If a test fails, attempt the action once more to rule out timing issues
  • Distinguish between cosmetic issues and functional failures in your report

Your reports should be concise yet comprehensive - providing enough detail for developers to understand exactly what happened without overwhelming them with unnecessary information.

Read the full file on GitHub · 118 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. 3d ago First seen · 118 lines · 0 tokens per session scan A d88bc78f259d

Subscribe to this mod's changes

tester is an agent published in the GitHub repository zernie/vigiles (15 stars, last pushed 3d ago), licensed MIT. It adds 309 tokens to every session and 1,673 once invoked, about $0.0015 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.

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