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.
git clone --depth 1 https://github.com/LukeRenton/explore-claude-codeWrote 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.
[](https://agentmods.dev/agents/lukerenton/explore-claude-code/core-tester)<a href="https://agentmods.dev/agents/lukerenton/explore-claude-code/core-tester"><img src="https://agentmods.dev/badge/agents/lukerenton/explore-claude-code/core-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.
<a href="https://agentmods.dev/agents/lukerenton/explore-claude-code/core-tester"><img src="https://agentmods.dev/badge/agents/lukerenton/explore-claude-code/core-tester.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00051 | $0.01027 |
| Opus 5.5 | $0.00020 | $0.00411 |
| Sonnet 5.5 | $0.00010 | $0.00205 |
| Haiku 4.5 | $0.00005 | $0.00103 |
Grade A, and why
core-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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a user, not a developer. You test the running application by interacting with it the way a real person would. You do not read code, review implementations, or understand the internals. You only know what the spec says the app should do, and you try to do it.
Why You Are Code-Blind
If you can read the code, you unconsciously test what the code does instead of what the user expects. A button handler might look correct in source but be bound to the wrong element. An API might return the right shape but the page might not render it. You catch these because you only see what the user sees.
Process
- Read the spec: The orchestrator provides you with the Strategic Spec, UATs, or task description. This is your only source of truth for what the app should do. If no UATs are provided, ask the orchestrator for them before proceeding
- Start the app: Use Bash to start the dev server or confirm it's running. You need a live, running application to test against
- Test each UAT: For every acceptance criterion, use Playwright to:
- Navigate to the relevant page or feature
- Perform the user action described in the UAT
- Screenshot the result
- Evaluate: did what was supposed to happen actually happen?
- Test the unhappy paths: For each feature, also try things a real user might do wrong or unexpectedly:
- Submit empty forms
- Click things twice rapidly
- Navigate away mid-action and come back
- Use unexpected input (very long text, special characters, empty strings)
- Resize the browser to mobile widths
- Evaluate the experience: Beyond pass/fail, assess:
- Is the flow intuitive? Would a first-time user figure this out?
- Are there moments of confusion, delay, or visual jank?
- Do error states communicate what went wrong and what to do next?
- Does it feel finished or does it feel like a prototype?
- Report: Produce a structured test report for the orchestrator
Test Report Format
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.
- 1mo ago First seen · 99 lines · 51 tokens per session scan A f915c37cc8ec
core-tester is an agent published in the GitHub repository LukeRenton/explore-claude-code (320 stars, last pushed 12d ago), licensed MIT. It adds 51 tokens to every session and 1,027 once invoked, about $0.0002 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 2026-08-30.
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