Feature flags are a powerful tool for controlled rollouts, A/B testing, and kill switches. They let you deploy code without exposing features, test in production safely, and roll back instantly when problems arise.
But feature flags have a dark side: they accumulate. A flag gets added for a feature launch, the launch succeeds, and the flag stays. Months later, your codebase is littered with conditional logic for flags that have been at 100% for so long nobody remembers they exist.
This flag debt creates real problems. Code becomes harder to read with nested conditionals everywhere. Testing requires considering flag combinations that don't actually vary in production. Developers new to the codebase can't distinguish temporary experiments from permanent architecture. AI tools like Devonair can identify and clean up these stale flags automatically.
AI agents can identify stale flags, remove them safely, and clean up the conditional code they protected.
How Feature Flag Debt Accumulates
Understanding the lifecycle helps prevent debt.
The Hopeful Launch
A new feature ships behind a flag. The team plans to remove the flag "right after launch stabilizes." The launch succeeds. The team moves to the next feature. The flag remains.
The Abandoned Experiment
An A/B test runs, the winning variant is chosen, but removing the losing code path feels risky. Both variants stay in the code, selected by a flag that never varies anymore.
The Emergency Kill Switch
A flag gets added during an incident as a quick disable mechanism. The incident passes, but the flag stays "just in case."
The Forgotten Migration
A flag gates migration between old and new implementations. Migration completes, but the flag and old implementation linger because removal feels like work with no visible benefit.
The Compound Effect
Each flag individually seems fine to keep. But 50 flags mean 50 code paths that never execute in production, 50 test configurations that don't matter, and exponential complexity when flags interact.
Identifying Stale Flags
First, find the flags that should be removed.
Usage Analysis
@devonair identify feature flags that have been at consistent values for over 30 days
If a flag never varies, it's not flagging anything.
Code Reference Analysis
@devonair find feature flags referenced in code but not configured in the flag system
Orphaned flags indicate incomplete cleanup.
Evaluation History
@devonair analyze flag evaluation history and identify flags always returning true
Configuration Audit
@devonair compare flag configuration across environments and identify consistently enabled flags
Same value everywhere means it's not really a flag.
Flag Categories for Cleanup
Different flag types need different handling.
Release Flags
Flags for gradual rollouts that completed:
@devonair identify release flags at 100% for more than 14 days
If it's fully rolled out, remove the flag.
Experiment Flags
Flags for A/B tests that concluded:
@devonair identify experiment flags with decided winners that haven't been cleaned up
Remove losing variants and the experiment infrastructure.
Ops Flags
Flags for operational control:
@devonair identify ops flags that have never been toggled
Unused kill switches just add complexity.
Permission Flags
Flags for feature access control:
@devonair identify permission flags that grant access to all users
If everyone has access, you don't need a flag.
Safe Flag Removal
Removing flags requires removing all references.
Code Cleanup
@devonair remove feature flag isNewCheckoutEnabled and all conditional code paths
The agent:
- Finds all flag references
- Evaluates which code path to keep
- Removes conditionals
- Cleans up unused imports
Test Cleanup
@devonair remove test cases for feature flag variants that no longer exist
Tests for removed flags waste CI time.
Configuration Cleanup
@devonair remove flag definition from flag configuration system
Remove from the source of truth.
Documentation Cleanup
@devonair remove feature flag from documentation and runbooks
Outdated documentation causes confusion.
Removal Patterns
The Simple Removal
Flag with clear on/off paths:
@devonair remove flag showBetaFeatures and keep the enabled code path
Delete flag checks, keep the winning code.
The Complex Removal
Flags that affect multiple code locations:
@devonair remove flag newPaymentFlow across all 23 usage sites
The agent handles consistency across files.
The Nested Removal
Flags inside other flag blocks:
@devonair clean up nested feature flag conditionals in /src/checkout
Untangle nested conditionals cleanly.
The Gradual Removal
Large flag removals in phases:
@devonair remove feature flag from /src/components this week
@devonair remove remaining feature flag references next week
Prevention Strategies
Stop flag debt before it starts.
Expiration Dates
@devonair add expiration dates to all new feature flags
@devonair alert when flags exceed their planned lifespan
Cleanup Reminders
@devonair schedule: remind teams of flags older than 90 days
Regular reminders prevent permanent "temporary" flags.
Flag Limits
@devonair alert when total feature flag count exceeds threshold
Caps force cleanup before adding new flags.
Ownership Assignment
@devonair assign owner to each feature flag
Flags with owners get cleaned up. Orphan flags persist forever.
Automated Cleanup Workflows
PR-Level Prevention
@devonair on PR: warn if adding feature flag without expiration date
@devonair on PR: suggest removal if modifying code with stale flag
Scheduled Cleanup
@devonair schedule weekly: identify flags eligible for removal and create cleanup PRs
Automated cleanup PRs keep flag debt manageable.
Post-Launch Cleanup
@devonair when flag reaches 100%: schedule cleanup PR in 14 days
Automatic follow-up after successful launches.
Quarterly Audits
@devonair schedule quarterly: comprehensive feature flag audit with cleanup recommendations
Regular deep review catches what automation misses.
Testing After Removal
Flag removal changes code paths.
Verification Testing
@devonair remove flag and verify tests pass
Existing tests should cover the remaining code path.
Coverage Analysis
@devonair verify test coverage after flag removal
Ensure removed paths don't leave gaps.
Production Verification
@devonair after deployment: verify behavior matches pre-removal with flag enabled
Confirm the change is invisible to users.
Handling Complex Flags
Some flags are harder to remove.
Deeply Integrated Flags
Flags referenced throughout the codebase:
@devonair analyze impact of removing flag newUserExperience across 150 references
Understand the scope before starting.
Performance Flags
Flags controlling performance-sensitive code:
@devonair remove performance flag with careful attention to the optimized path
Ensure you keep the performant implementation.
Data Migration Flags
Flags controlling data format:
@devonair verify all data migrated before removing flag for old format handling
Don't remove code needed to read existing data.
External Integration Flags
Flags for third-party integrations:
@devonair verify integration is stable before removing fallback flag
Ensure stable integrations before removing fallbacks.
Measuring Flag Health
Track flag hygiene over time.
Flag Count Tracking
@devonair track total feature flag count over time
Count should stay relatively stable.
Flag Age Distribution
@devonair report on feature flag age distribution
Too many old flags indicates cleanup backlog.
Cleanup Rate
@devonair track flags added vs. flags removed per month
Removals should keep pace with additions.
Debt Score
@devonair calculate feature flag debt score based on age and unused flags
Single metric for flag health.
Organizational Practices
Beyond automation, practices matter.
Flag Ownership
Every flag has an owner. Owners are responsible for cleanup.
Flag Reviews
@devonair include feature flag impact in PR reviews
Review flag additions and require cleanup plans.
Definition of Done
Cleanup is part of feature completion, not a separate task.
Documentation Requirements
@devonair require documentation for each feature flag: purpose, owner, planned removal
Future cleanup is easier with context.
Getting Started
Audit current state:
@devonair inventory all feature flags with age, value, and usage statistics
Identify quick wins:
@devonair list flags at 100% for over 30 days with fewer than 10 code references
Start removing:
@devonair remove the oldest stale flag that has minimal code impact
Set up prevention:
@devonair require expiration dates on new flags and alert when exceeded
Feature flags should enable rapid, safe deployment - not create permanent code complexity. When stale flags clean up automatically, you get the benefits of flags without the debt.
FAQ
How long should a flag live?
Release flags: 2-4 weeks after full rollout. Experiment flags: remove immediately after decision. Ops flags: keep indefinitely but audit annually. Most flags shouldn't survive a quarter.
What if we're not sure a flag is safe to remove?
If you can't determine if a flag is safe to remove, the flag is already causing problems. Investigate, document what you find, then decide. Uncertainty is a sign of accumulated debt.
Should we keep flags for rollback capability?
No. Version control and deployment tooling provide rollback. Keeping flag code "just in case" means keeping dead code forever. If you need to rollback, revert the removal PR.
What about flags that are sometimes on, sometimes off?
Those are working as intended and shouldn't be removed. Focus on flags that are always the same value - those aren't flagging, they're just adding complexity.