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name: feature-flagging description: Designs safe feature rollouts with flags, cohort targeting, kill switches, and cleanup plans. Use when launching, gating, or retiring feature flags.

Feature flagging

Purpose

Guide safe progressive delivery using feature flags: cohort sizing, success/rollback criteria, kill switches, and flag lifecycle hygiene.

When to Use

• User asks about feature flags, gradual rollout, kill switch, or flag cleanup.
• Planning canary/percentage rollouts with observability guardrails.
• Separating release flags from entitlements/permissions.

When NOT to Use

• A/B experiment design and statistics → ab-experimentation.
• Infrastructure feature stores you do not have context for—gather vendor/docs first.
• Code implementation without flag context → implement-features.

Expected Outcome

• Rollout plan with cohort, metrics, rollback/kill steps, and flag lifecycle (owner, expiry).
• Clear distinction between release toggles and permission flags.

Inputs to Gather

• Flag name/key, default state, and targeting rules.
• Success metrics and alert thresholds.
• Owner, expiry/removal ticket, and environments.
• On-call kill-switch procedure.

Workflow

1. Classify flag type (release vs permission vs experiment).
2. Define default-off/on rationale and smallest first cohort.
3. Set success metrics and rollback triggers before expanding.
4. Document kill-switch steps for on-call.
5. Plan removal ticket to avoid long-lived debt.
6. Pair with monitor-slos / observability for guardrails during rollout.

Domain guidance

• Prefer small cohorts first; define success and rollback criteria before expanding.
• Separate release flags from permission or entitlements.
• Every flag needs: owner, expiry or removal ticket, default-off or default-on rationale.
• Document kill-switch steps for on-call.

Avoid long-lived flags without cleanup plans.

Tool Availability Rules

Access	Behavior
Full tool access	Update flag config via integrated tools when approved.
Read-only	Produce rollout plan and ticket text.
No flag platform	Architectural guidance only; no fabricated flag state.

Related tool sets

• github
• jira

Review / Decision / Execution Criteria

• Rollback path tested or documented before wide rollout.
• No permission checks hidden behind release flags without review.
• Expiry or removal ticket required for new flags.

Output Format

1. Flag inventory (in scope).
2. Rollout phases and cohorts.
3. Metrics and rollback/kill triggers.
4. Lifecycle (owner, expiry).
5. Risks and open questions.

Quality Bar

• On-call can execute kill switch from your doc alone.

Safety and Boundaries

• Confirm production flag changes affecting all users.
• Do not fabricate current flag targeting state.

Escalation / Dispatch Rules

• Experiment analysis → ab-experimentation.
• Incident during rollout → lead-incidents.

References

• skills/old_skills.json (feature-flagging).
• skills/skill.instruction.md, skills/meta.instructions.md