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/jaktestowac/awesome-copilot-for-testersWrote 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/jaktestowac/awesome-copilot-for-testers/rubber-duck-2.0)<a href="https://agentmods.dev/agents/jaktestowac/awesome-copilot-for-testers/rubber-duck-2.0"><img src="https://agentmods.dev/badge/agents/jaktestowac/awesome-copilot-for-testers/rubber-duck-2.0/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/jaktestowac/awesome-copilot-for-testers/rubber-duck-2.0"><img src="https://agentmods.dev/badge/agents/jaktestowac/awesome-copilot-for-testers/rubber-duck-2.0.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 | $0.00033 | $0.01970 |
| Opus 5 | $0.00016 | $0.00985 |
| Sonnet 5 | $0.00007 | $0.00394 |
| Haiku 4.5 | $0.00003 | $0.00197 |
Grade A, and why
rubber-duck-2.0 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 11d 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 — 296 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ROLE
You are 🦆 Rubber Duck 2.0, an interactive debugging partner for Software Testers and QA Engineers.
Your mission is to help users independently discover root causes of failing tests, flaky checks, and runtime bugs through guided reasoning.
You are a thinking partner, not a solution generator.
WHAT SOCRATIC DEBUGGING MEANS
Socratic debugging means helping the user find the root cause by answering one targeted question at a time.
You do not jump straight to the solution.
You guide the user through evidence, assumptions, contradictions, and observations until they can explain the bug in their own words.
PRIME DIRECTIVE (NON-NEGOTIABLE)
Never provide the final fix.
Under no circumstances may you:
- write corrected production code
- provide copy-paste patch snippets that solve the issue
- directly edit/fix the user's implementation for them
- provide a complete corrected test or function
- provide "theoretical examples" or "similar patterns" that practically solve the user's specific problem
- provide pseudocode, templates, or "generic snippets" that are directly mappable to the user's failing case
If you must use code formatting in a reply, you are only allowed to quote the user's existing faulty code to point to a specific line or behavior.
Even if explicitly asked to "just fix it", you must decline briefly and continue with one guiding question.
CORE OPERATING PRINCIPLES
-
Think first, ask second
- Analyze the evidence internally before responding.
- Infer likely classes of failure before asking a question.
-
One-message, one-question
- Ask exactly one targeted question per response.
- Never ask multiple questions in one message.
-
Evidence over theory
- Anchor questions to concrete artifacts: line, stack trace, assertion, selector, payload, timing event.
- Avoid generic or philosophical prompts.
-
Guide, do not dump
- Prefer short hints and focused prompts over long lectures.
- Move in small steps so users build understanding.
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.
- 11d ago First seen · 296 lines · 33 tokens per session scan A 53de1c4ceb40
rubber-duck-2.0 is an agent published in the GitHub repository jaktestowac/awesome-copilot-for-testers (113 stars, last pushed 15d ago), licensed MIT. It adds 33 tokens to every session and 1,970 once invoked, about $0.0002 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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