sumo-qa-strengthening-tests

sumo-qa-strengthening-tests is a skill for Claude Code from sumithr/sumo-qa. It costs 69 tokens per session (2,745 once invoked), scanned A, original, Apache-2.0.

A guide for improving tests after mutation testing finds surviving mutants, which are simulated code changes that existing tests failed to catch. It handles one survivor at a time and changes only test code.

In plain words
What is it for?
Use it to investigate surviving mutants, remove tautological assertions, choose a suitable testing technique, and write stronger tests without changing production code.
Why use it?
It helps distinguish weak tests from mutants that do not matter in practice. It also prevents tests from merely repeating the implementation instead of checking real behaviour.

Skill for Claude Code

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

Part of the sumo-qa plugin — 20 skills, 2 agents, 3 hooks, 1 MCP server shipped together

Good fit Use it to investigate surviving mutants, remove tautological assertions, choose a suitable testing technique, and write stronger tests without changing production code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sumithr/sumo-qa/sumo-qa-strengthening-tests
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 sumithr/sumo-qa --skill sumo-qa-strengthening-tests
Clone the repo
git clone --depth 1 https://github.com/sumithr/sumo-qa

Made for: Claude Code.

Or install sumo-qa, the plugin that ships this one along with the rest of its 20 skills, 2 agents, 3 hooks, 1 MCP server.

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 sumo-qa-strengthening-tests

README.md
[![agentmods](https://agentmods.dev/badge/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests/github.svg)](https://agentmods.dev/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests)
Your own site
<a href="https://agentmods.dev/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests"><img src="https://agentmods.dev/badge/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests/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 sumo-qa-strengthening-tests

Your own site · 80×15
<a href="https://agentmods.dev/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests"><img src="https://agentmods.dev/badge/skills/sumithr/sumo-qa/sumo-qa-strengthening-tests.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,745 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 $0.00069 $0.02745
Opus 5 $0.00034 $0.01373
Sonnet 5 $0.00014 $0.00549
Haiku 4.5 $0.00007 $0.00275

Measured 9d ago against content hash d5e53513f572, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

sumo-qa-strengthening-tests 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 9d 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/sumo-qa-strengthening-tests/SKILL.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Strengthening tests

Help the user kill weak assertions and surviving mutants by walking each survivor one at a time: triage tautology vs real, pick a technique, draft the strengthening test, confirm. The user has judgement context (is this mutant "real" given how the code is consumed in practice?) the AI can't infer from the report alone — surface it through questions, don't assume it.

Announce at start: "Killing the mutation survivors, one at a time."

Output discipline (mandatory)

Inherits the global discipline from using-sumo-qa: output discipline (never surface internal taxonomy labels — say "behaviour change in pricing", not "Classification: business_logic_change"), output economy (spend output on findings not framing; no preamble or self-narration; one question per turn; no closing pleasantries), knowledge authority hierarchy, internal scaffolding stays internal, and specialty-tool fit.

The Iron Law

PRODUCTION CODE STAYS UNCHANGED. Only test code moves; equivalent mutants get suppressed in tool config, not "killed" by tautological tests that re-state the production code.

When to Use

sumo-qa-deciding-approach routes here for strengthen-test-coverage. User intents:

  • "raise coverage on module X"
  • "Pitest shows N surviving mutants — kill them"
  • "Stryker / mutmut surfaced weak assertions"
  • "strengthen the tests on the order calculator"

Production code is locked. The job is to make the EXISTING tests stronger.

Checklist

You MUST work through these in order. Steps 1–3 are AI-only homework (no user questions). The user's confirmation gates steps 4 onward, and steps 5–7 repeat per target (each surviving mutant, or — when no report exists — each weak assertion the user named, which skips straight to step 7).

Read the full file on GitHub · 112 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. 9d ago First seen · 112 lines · 69 tokens per session scan A d5e53513f572

Subscribe to this mod's changes

sumo-qa-strengthening-tests is a skill published in the GitHub repository sumithr/sumo-qa (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 69 tokens to every session and 2,745 once invoked, about $0.0003 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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