/feature-flag-check

Feature Flag Investigation

> **Project context:** Values in angle brackets below (e.g. `<scheme>`, `<JIRA_KEY>`, `<flag-key-enum>`) are resolved at runtime — detect them from the project (`xcodebuild -list -json` for the scheme, `git`/`gh` for repo & owner, the branch name for the Jira key, a codebase search for flag/font files), or ask if they cannot be inferred. This plugin ships no per-project config.

Investigate the feature flag **$ARGUMENTS** and produce a detailed investigation for removal.

**Output:** Creates an investigation file at `docs/feature-flags/issues/$ARGUMENTS.md` that serves as the "issue" for this cleanup. The `/feature-flag-remove` command will read this investigation before executing the removal.

Steps

1. Find the Flag Definition

Search for the flag in RemoteConfig files:

Grep: "$ARGUMENTS" in <flag-key-file>
Grep: "$ARGUMENTS" in <flag-defaults-file>.swift

Document:

• The exact case name in `<flag-key-enum>`
• The default value from `<flag-defaults-file>`
• The value type (Bool, String, Int, etc.)

2. Find All Flag Usages

Search for all code using this flag:

Grep: "<flag-key-enum>.$ARGUMENTS" in *.swift
Grep: ".$ARGUMENTS" in *.swift (for shorthand usage)
Grep: the flag's string key in all files

For each usage, note:

• File path
• How the flag is read (remoteConfig.bool(), remoteConfig.string(), etc.)
• What code path is gated (true vs false branch)
• Whether it's the only flag check or combined with others

3. Trace Code Paths

For each flag usage, trace what code is affected:

**If flag guards a feature:**

• Find all ViewControllers/Views involved
• Find all ViewModels involved
• Find all Repositories/DataSources involved
• Find all Models specific to the feature
• Find navigation/coordinator logic
• Find any managers or helpers

**If flag guards a UI element:**

• Find the specific view/component
• Check if it has dedicated logic or is inline

**If flag guards a string/config value:**

• Find where the value is used
• Check if removal requires a replacement value

4. Check Firebase Remote Config

Ask user to verify in Firebase Console:

• Current production value
• Current staging value
• Last time the flag was changed
• Whether it's safe to assume the flag is permanently ON or OFF

5. Identify Dead Code

Based on the flag's permanent value, identify:

• Code that will NEVER run (dead code to delete)
• Code that will ALWAYS run (keep, remove conditional)
• Code that needs the conditional simplified

6. Find Related Tests

Search for tests that reference this flag:

Grep: "$ARGUMENTS" in <scheme>Tests/
Grep: MockRemoteConfig with flag setup

Note which tests need updating vs deletion.

7. Assess Complexity

Rate the cleanup complexity:

| Complexity | Criteria | |------------|----------| | **Low** | String config, simple bool, <5 usages, no UI | | **Medium** | Feature toggle, 5-15 usages, some UI, some tests | | **High** | Major feature, >15 usages, full module, many tests |

8. Write the Investigation File

Create `docs/feature-flags/issues/$ARGUMENTS.md`:

# Investigation: $ARGUMENTS

> Generated: <date>
> Complexity: <Low/Medium/High>

## Flag Definition

| Property | Value |
|----------|-------|
| <flag-key-enum> | `$ARGUMENTS` |
| Type | <Bool/String/Int> |
| Default Value | <value> |
| Production Value | <value> (verify in Firebase) |

## Current Usages (<count>)

| File | Line | Usage |
|------|------|-------|
| ... | ... | ... |

## Affected Code

### Files to Delete
| File | Purpose | Lines |
|------|---------|-------|
| ... | ... | ... |

### Files to Modify
| File | Change Required |
|------|-----------------|
| ... | ... |

### Tests to Update
| Test File | Change |
|-----------|--------|
| ... | ... |

## Removal Plan

1. <step 1>
2. <step 2>
...

## Risks

- <any risks or dependencies to watch>

## Recommendation

<SAFE TO REMOVE / NEEDS DISCUSSION / BLOCKED BY X>

9. Update Status File

Add the flag to "In-Progress" section of `docs/feature-flags/status.md` if user wants to proceed.

Notes

• Always verify production flag value in Firebase before proceeding
• Some flags may be A/B tests still running - do not remove
• Check the team's pre-approved flags list (Notion or equivalent tracker)