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.
npx skills add JakubMikolajek/codex-skills-collection --skill feature-flagsgit clone --depth 1 https://github.com/JakubMikolajek/codex-skills-collectionWrote 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/skills/jakubmikolajek/codex-skills-collection/feature-flags)<a href="https://agentmods.dev/skills/jakubmikolajek/codex-skills-collection/feature-flags"><img src="https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/feature-flags/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/skills/jakubmikolajek/codex-skills-collection/feature-flags"><img src="https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/feature-flags.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 | $0.00059 | $0.02544 |
| Opus 5 | $0.00030 | $0.01272 |
| Sonnet 5 | $0.00012 | $0.00509 |
| Haiku 4.5 | $0.00006 | $0.00254 |
Grade A, and why
feature-flags 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 12d 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 — 291 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Feature Flags
A feature flag is a conditional code path. Done well, it enables safe deployments, gradual rollouts, and instant rollback without a redeploy. Done poorly, it becomes permanent technical debt that nobody dares remove.
When to Use
- Deploying a risky feature that needs a kill switch
- Rolling out a feature to a percentage of users before full release
- Running an A/B test or experiment
- Separating code deployment from feature activation (deploy dark, enable later)
- Giving ops teams the ability to disable a feature without a code deploy
When NOT to Use
- Permanent configuration values that will never change — use environment variables
- Access control and authorization — use role/permission systems, not flags
- Features that have been fully rolled out and will never be turned off — remove the flag
- Debugging toggles that only a developer will ever use — use environment variables or log levels
Flag Taxonomy
Choose the right flag type before implementing:
| Type | Purpose | Lifespan | Owner |
|---|---|---|---|
| Kill switch | Disable a feature instantly without deploy | Short — remove after feature is stable | Ops / on-call |
| Release flag | Gate a feature during rollout | Short — remove after full rollout | Engineering |
| Experiment flag | A/B test or multivariate experiment | Short — remove after analysis | Product |
| Ops flag | Tune behavior in production (timeouts, batch sizes) | Long-lived — can be permanent | Ops |
| Permission flag | Enable feature for specific users/plans | Long-lived — tied to business model | Product |
Most flags should be short-lived. Long-lived flags are acceptable only for ops and permission flags. A release flag that is still in the codebase 3 months after full rollout is flag debt.
Core Principles
Flags are Not Free
Every flag adds a branch in the code. Every branch adds cognitive load. Every flag has a removal cost. The answer to "should we flag this?" is not automatically yes — define a flag lifecycle at creation time.
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.
- 12d ago First seen · 291 lines · 59 tokens per session scan A 68bf5b9bc035
feature-flags is a skill published in the GitHub repository JakubMikolajek/codex-skills-collection (5 stars, last pushed 7d ago), licensed MIT. It adds 59 tokens to every session and 2,544 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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