feature-flag-testing

feature-flag-testing is a skill for Claude Code from aks-builds/quality-skills. It costs 130 tokens per session (2,526 once invoked), scanned A, original, MIT.

A guide for testing code that changes according to feature flags, which are settings used to turn features on, off, or on for selected users. It covers variations, flag combinations, gradual rollouts, experiments, and emergency shutoffs.

In plain words
What is it for?
Use it to test boolean or multi-option flags, percentage and attribute-based targeting, combinations of flags, canary releases, A/B tests, and kill-switch behavior.
Why use it?
It helps reveal broken code paths and interactions that can be missed when feature flags are treated as untested settings. It also checks that gradual releases and kill switches behave as intended.

Skill for Claude Code

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

Part of the quality-skills plugin — 57 skills shipped together

Good fit Use it to test boolean or multi-option flags, percentage and attribute-based targeting, combinations of flags, canary releases, A/B tests, and kill-switch behavior.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aks-builds/quality-skills/feature-flag-testing
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 aks-builds/quality-skills --skill feature-flag-testing
Clone the repo
git clone --depth 1 https://github.com/aks-builds/quality-skills

Made for: Claude Code.

Or install quality-skills, the plugin that ships this one along with the rest of its 57 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 feature-flag-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/aks-builds/quality-skills/feature-flag-testing/github.svg)](https://agentmods.dev/skills/aks-builds/quality-skills/feature-flag-testing)
Your own site
<a href="https://agentmods.dev/skills/aks-builds/quality-skills/feature-flag-testing"><img src="https://agentmods.dev/badge/skills/aks-builds/quality-skills/feature-flag-testing/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 feature-flag-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/aks-builds/quality-skills/feature-flag-testing"><img src="https://agentmods.dev/badge/skills/aks-builds/quality-skills/feature-flag-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 130 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,526 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 $0.00130 $0.02526
Opus 5 $0.00065 $0.01263
Sonnet 5 $0.00026 $0.00505
Haiku 4.5 $0.00013 $0.00253

Measured 8d ago against content hash 1b4b92e3eaa9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

feature-flag-testing 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 8d 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/feature-flag-testing/SKILL.md · 253 lines

How it starts

The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Feature Flag Testing

You are an expert in testing feature-flag-driven code — verifying that each variation works, that flag combinations don't collide, that gradual rollouts behave as designed, and that kill-switches reliably stop bad code. Your goal is to help engineers extend their test discipline to flag-controlled code paths instead of treating flags as untestable "magic." Don't fabricate vendor APIs or flag-evaluation rules. When uncertain, point the reader to the vendor's docs.

Initial Assessment

Check .agents/qa-context.md (fallback: .claude/qa-context.md) before answering. Pay attention to:

  • Vendor / library — LaunchDarkly, Split.io, Unleash, ConfigCat, Flagsmith, Statsig, Optimizely, or self-hosted. SDKs and evaluation semantics differ.
  • Flag types in use — release toggles (short-lived), permission toggles (long-lived), experiment toggles, operational toggles (kill switches).
  • Targeting complexity — boolean per-user, percentage rollouts, multi-variation, attribute-based, segment-based.
  • Flag count — 50 flags is manageable; 500 flags is its own discipline.
  • Cleanup discipline — flags piling up uncleaned for years is a real codebase health issue.

If the file does not exist, ask: vendor, flag types, targeting complexity, count, cleanup practices.


Why flag testing is non-obvious

Flag-controlled code introduces hidden complexity:

  • Variation coverage: a flag with 2 values has 2 paths to test. 5 flags with 2 values = 32 combinations.
  • Default behavior: what happens when the SDK fails or the flag evaluator is unreachable? Tests rarely cover this.
  • Stale flags: flag is "fully rolled out" but the off-branch code still exists, untested, until someone re-enables it accidentally.
  • Combinatorial drift: flag A's variations interact with flag B's variations in unintended ways.
  • Targeting bugs: 50% rollout actually delivers to 70% because the hashing isn't uniform.

Test-strategy implication: flagged code is a multi-variant code path, and your tests need to know that.

Read the full file on GitHub · 253 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. 8d ago First seen · 253 lines · 130 tokens per session scan A 1b4b92e3eaa9

Subscribe to this mod's changes

feature-flag-testing is a skill published in the GitHub repository aks-builds/quality-skills (2 stars, last pushed 5d ago), licensed MIT. It adds 130 tokens to every session and 2,526 once invoked, about $0.0006 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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