duck-triage

duck-triage is a skill for Claude Code from sprngr/rubber-duck. It costs 37 tokens per session (1,196 once invoked), scanned A, original, MIT.

A test-planning and bug-triage guide that checks what your tests cover and helps classify how serious a bug is.

In plain words
What is it for?
Use it when deciding what to test, reviewing coverage gaps, or assessing a bug before a pull request. It can guide test direction, but leaves implementation and test-writing decisions to you.
Why use it?
It exposes missing test coverage and focuses attention on the smallest checks that can catch regressions. It also identifies missing evidence before recommending a severity.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the rubber-duck plugin — 17 skills shipped together

Good fit Use it when deciding what to test, reviewing coverage gaps, or assessing a bug before a pull request. It can guide test direction, but leaves implementation and test-writing decisions to you.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sprngr/rubber-duck/duck-triage
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.

Any agent
npx skills add sprngr/rubber-duck --skill duck-triage
Clone the repo
git clone --depth 1 https://github.com/sprngr/rubber-duck

Made for: Claude Code.

Or install rubber-duck, the plugin that ships this one along with the rest of its 17 skills.

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 duck-triage

README.md
[![agentmods](https://agentmods.dev/badge/skills/sprngr/rubber-duck/duck-triage/github.svg)](https://agentmods.dev/skills/sprngr/rubber-duck/duck-triage)
Your own site
<a href="https://agentmods.dev/skills/sprngr/rubber-duck/duck-triage"><img src="https://agentmods.dev/badge/skills/sprngr/rubber-duck/duck-triage/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 duck-triage

Your own site · 80×15
<a href="https://agentmods.dev/skills/sprngr/rubber-duck/duck-triage"><img src="https://agentmods.dev/badge/skills/sprngr/rubber-duck/duck-triage.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,196 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 $0.00037 $0.01196
Opus 5 $0.00018 $0.00598
Sonnet 5 $0.00007 $0.00239
Haiku 4.5 $0.00004 $0.00120

Measured 11d ago against content hash 35481ad888d5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

duck-triage 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.

skills/duck-triage/SKILL.md · 150 lines

How it starts

The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test coverage and bug triage 🦆. Find what tests miss. Classify what bugs matter. Keep language terse and practical.

Purpose

Classify bug severity and expose missing test coverage with smallest runnable checks.

Philosophy Guardrails (skill-local)

Inherit shared guardrails from references/GUARDRAILS.md.

Skill-specific delta:

  • Recommend severity and test direction; user decides implementation/test-writing actions.

Activation

Use for test coverage planning, bug severity triage, and pre-PR test recommendations.

Method

1. Clarify context (if repro/spec missing)

  • ask 1-3 targeted clarifying questions when context is incomplete

  • state assumptions explicitly when evidence is missing

  • Ask one targeted clarifying question about missing repro/spec first.

If evidence is missing, include explicit marker:

  • missing evidence: with concise list (logs/repro steps/release window/affected scope)

2. Apply Duck Ladder (test planning)

Before asking for new tests, check:

  1. Does behavior already have reliable coverage?
  2. Can existing test be extended instead of new file/suite?
  3. Smallest runnable check that fails on regression?

3. Triage workflow

For bug severity:

  1. Collect evidence first: repro artifact, failing path, existing test coverage map.
  2. Reproduce the reported behavior.
  3. Classify using severity matrix (below).
  4. Check: is this a regression or pre-existing?
  5. Check: does existing test coverage exist? If not, flag missing coverage as contributing factor.
  6. Output: severity + brief rationale + which test to add.

Bug severity classification:

Level Criteria Action Examples
🔴 P0 — Critical Data loss, security breach, all users blocked Hotfix immediate Wrong money sent, API auth bypass
🟠 P1 — High Major feature broken, workaround exists Sprint priority Search broken for one locale
🟡 P2 — Medium Partial feature broken, degraded UX Next iteration Icon misaligned, slow query
🔵 P3 — Low Cosmetic, edge case, typo Backlog Missing comma, label casing
⚪ P4 — Informational Nice-to-have, not a bug Discuss Suggestion, enhancement

Read the full file on GitHub · 150 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 11d ago First seen · 150 lines · 37 tokens per session scan A 35481ad888d5

Subscribe to this mod's changes

duck-triage is a skill published in the GitHub repository sprngr/rubber-duck (8 stars, last pushed yesterday), licensed MIT. It adds 37 tokens to every session and 1,196 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 2026-08-31.

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