LaunchDarkly Flag Cleanup

LaunchDarkly Flag Cleanup

A workflow for safely removing feature flags from codebases while preserving production behavior. This skill uses LaunchDarkly as the source of truth to determine removal readiness and the correct forward value.

Prerequisites

This skill requires the LaunchDarkly MCP server to be configured in your environment.

Required MCP tools:

• get-environments
• get-feature-flag
• get-flag-status-across-environments
• get-code-references

Core Principles

1. Safety First: Always preserve current production behavior.
2. LaunchDarkly as Source of Truth: Never guess. Query the actual configuration.
3. Clear Communication: Explain reasoning in PR descriptions.
4. Follow Conventions: Respect existing code style and structure.

Flag Removal Workflow

Step 1: Identify Critical Environments

Use get-environments with the project key to find environments marked as critical (typically production, staging, or user-specified).

Step 2: Fetch Flag Configuration

Use get-feature-flag to retrieve the full configuration. Extract:

• variations: Possible values
• Per critical environment:
  • on: Whether enabled
  • fallthrough.variation: Variation index when no rules match
  • offVariation: Variation index when flag is off
  • rules: Targeting rules (complexity indicator)
  • targets: Individual context targets

Step 3: Determine Forward Value

The forward value replaces the flag in code.

Step 4: Assess Removal Readiness

Use get-flag-status-across-environments to check lifecycle status.

READY if ALL true:

• Status is launched or active in all critical environments
• Same variation served across all critical environments
• No targeting rules or individual targets in critical environments
• Flag is not already archived/​deprecated

PROCEED WITH CAUTION if:

• Status is inactive (no recent traffic)
• Zero evaluations in last 7 days (confirm with user)

NOT READY if:

• Status is new (still rolling out)
• Different variations across critical environments
• Complex targeting rules exist
• Critical environments differ in ON/​OFF state

Step 5: Check Code References

Use get-code-references to identify repositories. If the current repo isn't listed, inform the user. Note the count of other repositories for awareness.

Step 6: Remove Flag from Code

Search for all references and replace with the forward value:

1. Find evaluation patterns:

   • variation('flag-key', ...)
   • boolVariation('flag-key', ...)
   • featureFlags['flag-key']
   • SDK-specific and wrapper patterns

2. Replace with forward value:

   • Preserve the branch matching the forward value
   • Remove the dead branch and related code
   • If assigned to a variable, replace with the value directly

3. Clean up:

   • Remove unused imports/​constants
   • Avoid unrelated refactors
   • Double-check for orphaned exports or files created solely for the flag (unused components, hooks, helpers, styles, and test files)
   • If the repo uses an unused-export tool (e.g., lint rules, Knip, ts-prune), run it and remove any flag-related orphans it reports

Example transformation (forward value = true):

// Before
const showNewCheckout = await ldClient.variation('new-checkout-flow', user, false);
if (showNewCheckout) {
  return renderNewCheckout();
} else {
  return renderOldCheckout();
}

// After
return renderNewCheckout();

Step 7: Create Pull Request

Use the template in references/​pr-template.md for a structured PR description including removal summary, readiness assessment, and risk analysis.

Edge Cases

What NOT to Do

• Don't change code unrelated to flag cleanup.
• Don't refactor or optimize beyond flag removal.
• Don't remove flags still being rolled out.
• Don't guess the forward value.

Related Resources

• PR Template
• SDK Patterns