feature-flag-manager

Name: feature-flag-manager
Author: girijashankarj

27stars3forks

How to install feature-flag-manager?

girijashankarj/cursor-handbook/feature-flag-manager

$npx -y skills add girijashankarj/cursor-handbook --skill feature-flag-manager

Installs into the current project.

Summary

Create, manage, and clean up feature flags for gradual rollouts and safe deployments. Use when the user asks to add a feature flag, toggle, or manage feature gating.

Files · 1

View on GitHub

SKILL.md

1	# Skill: Feature Flag Manager
2
3	Implement feature flags for controlled rollouts, A/B testing, and safe deployments with cleanup workflows.
4
5	## Trigger
6	When the user asks to add a feature flag, gate a feature, set up gradual rollout, or clean up old flags.
7
8	## Prerequisites
9	- [ ] Feature to gate identified
10	- [ ] Rollout strategy decided (on/off, percentage, user segment)
11
12	## Steps
13
14	### Step 1: Choose Flag Strategy
15
16	\| Strategy \| When to Use \| Complexity \|
17	\|----------\|-------------\|-----------\|
18	\| Boolean toggle \| Simple on/off per environment \| Low \|
19	\| Percentage rollout \| Gradual rollout to % of users \| Medium \|
20	\| User segment \| Specific users, orgs, or roles \| Medium \|
21	\| A/B test \| Compare variants with metrics \| High \|
22	\| Kill switch \| Emergency disable of a feature \| Low \|
23
24	### Step 2: Define the Flag
25	- [ ] Name: `FEATURE_{DOMAIN}_{DESCRIPTION}` (e.g., `FEATURE_ORDERS_ASYNC_PROCESSING`)
26	- [ ] Type: boolean, number (percentage), string (variant)
27	- [ ] Default value: `false` (new features default to off)
28	- [ ] Description: one sentence explaining what it controls
29	- [ ] Owner: team or person responsible
30	- [ ] Expiry: target date for cleanup
31
32	### Step 3: Create Flag Configuration
33
34	```typescript
35	// config/feature-flags.ts
36	export const FeatureFlags = {
37	FEATURE_ORDERS_ASYNC_PROCESSING: {
38	key: 'FEATURE_ORDERS_ASYNC_PROCESSING',
39	description: 'Enable async order processing pipeline',
40	defaultValue: false,
41	owner: 'orders-team',
42	createdAt: '2026-04-12',
43	targetCleanup: '2026-06-12',
44	},
45	} as const;
46
47	export type FeatureFlagKey = keyof typeof FeatureFlags;
48	```
49
50	### Step 4: Implement Flag Check Utility
51
52	```typescript
53	// utils/feature-flags.ts
54	export function isFeatureEnabled(
55	flagKey: FeatureFlagKey,
56	context?: { userId?: string; orgId?: string }
57	): boolean {
58	const envValue = process.env[flagKey];
59	if (envValue !== undefined) {
60	return envValue === 'true' \|\| envValue === '1';
61	}
62	return FeatureFlags[flagKey].defaultValue;
63	}
64	```
65
66	### Step 5: Gate the Feature in Code
67
68	```typescript
69	// In handler/service:
70	if (isFeatureEnabled('FEATURE_ORDERS_ASYNC_PROCESSING', { userId })) {
71	await processOrderAsync(order);
72	} else {
73	await processOrderSync(order);
74	}
75	```
76
77	### Step 6: Add to Environment Config
78	- [ ] Add flag to `.env.example` with `false` default
79	- [ ] Add to staging `.env` with `true` for testing
80	- [ ] Keep production as `false` until ready for rollout
81
82	### Step 7: Add Tests for Both Paths
83	- [ ] Test with flag enabled
84	- [ ] Test with flag disabled
85	- [ ] Test flag default behavior (env var not set)
86
87	```typescript
88	describe('when FEATURE_ORDERS_ASYNC_PROCESSING is enabled', () => {
89	beforeEach(() => { process.env.FEATURE_ORDERS_ASYNC_PROCESSING = 'true'; });
90	afterEach(() => { delete process.env.FEATURE_ORDERS_ASYNC_PROCESSING; });
91
92	it('should process order asynchronously', async () => { /* ... */ });
93	});
94
95	describe('when FEATURE_ORDERS_ASYNC_PROCESSING is disabled', () => {
96	it('should process order synchronously', async () => { /* ... */ });
97	});
98	```
99
100	### Step 8: Document Rollout Plan
101	```markdown
102	## Rollout Plan: FEATURE_ORDERS_ASYNC_PROCESSING
103	1. Dev/Staging: Enable, run integration tests
104	2. Canary (5%): Monitor error rate and latency for 24h
105	3. Gradual (25% → 50% → 100%): Each stage monitored for 48h
106	4. Cleanup: Remove flag after 2 weeks at 100%
107	```
108
109	## Flag Cleanup Workflow
110
111	### When to Clean Up
112	- Flag has been at 100% for 2+ weeks
113	- No incidents related to the feature
114	- Target cleanup date reached
115
116	### Cleanup Steps
117	1. Remove the flag check — keep the "enabled" code path
118	2. Remove the "disabled" code path
119	3. Remove flag from `FeatureFlags` config
120	4. Remove from `.env` files
121	5. Remove flag-specific tests (keep the feature tests)
122	6. Update documentation
123
124	## Rules
125	- ALWAYS default new flags to `false` (off)
126	- ALWAYS set a cleanup target date when creating a flag
127	- ALWAYS test both code paths (enabled and disabled)
128	- NEVER nest feature flags (flag inside flag)
129	- NEVER use feature flags for permanent configuration — use config instead
130	- Flag names must be descriptive and follow `FEATURE_DOMAIN_DESCRIPTION` pattern
131	- Maximum 15 active flags at any time — clean up before adding more
132
133	## Completion
134	Feature flag created with config, utility function, code gating, tests, and rollout plan. Cleanup date documented.
135
136	## If a Step Fails
137	- Too many active flags: Audit and clean up stale flags first
138	- Complex branching: Consider a feature flag service (LaunchDarkly, Unleash) instead of env vars
139	- Tests flaky with flag: Ensure env var cleanup in `afterEach`
140	- Can't determine rollout strategy: Default to boolean toggle, upgrade later

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6 picks

Type

feature-flag-manager

27stars3forks

View on GitHub

How to install feature-flag-manager?

girijashankarj/cursor-handbook/feature-flag-manager

$npx -y skills add girijashankarj/cursor-handbook --skill feature-flag-manager

Installs into the current project.

Summary

Create, manage, and clean up feature flags for gradual rollouts and safe deployments. Use when the user asks to add a feature flag, toggle, or manage feature gating.

Files · 1

View on GitHub

SKILL.md

1	# Skill: Feature Flag Manager
2
3	Implement feature flags for controlled rollouts, A/B testing, and safe deployments with cleanup workflows.
4
5	## Trigger
6	When the user asks to add a feature flag, gate a feature, set up gradual rollout, or clean up old flags.
7
8	## Prerequisites
9	- [ ] Feature to gate identified
10	- [ ] Rollout strategy decided (on/off, percentage, user segment)
11
12	## Steps
13
14	### Step 1: Choose Flag Strategy
15
16	\| Strategy \| When to Use \| Complexity \|
17	\|----------\|-------------\|-----------\|
18	\| Boolean toggle \| Simple on/off per environment \| Low \|
19	\| Percentage rollout \| Gradual rollout to % of users \| Medium \|
20	\| User segment \| Specific users, orgs, or roles \| Medium \|
21	\| A/B test \| Compare variants with metrics \| High \|
22	\| Kill switch \| Emergency disable of a feature \| Low \|
23
24	### Step 2: Define the Flag
25	- [ ] Name: `FEATURE_{DOMAIN}_{DESCRIPTION}` (e.g., `FEATURE_ORDERS_ASYNC_PROCESSING`)
26	- [ ] Type: boolean, number (percentage), string (variant)
27	- [ ] Default value: `false` (new features default to off)
28	- [ ] Description: one sentence explaining what it controls
29	- [ ] Owner: team or person responsible
30	- [ ] Expiry: target date for cleanup
31
32	### Step 3: Create Flag Configuration
33
34	```typescript
35	// config/feature-flags.ts
36	export const FeatureFlags = {
37	FEATURE_ORDERS_ASYNC_PROCESSING: {
38	key: 'FEATURE_ORDERS_ASYNC_PROCESSING',
39	description: 'Enable async order processing pipeline',
40	defaultValue: false,
41	owner: 'orders-team',
42	createdAt: '2026-04-12',
43	targetCleanup: '2026-06-12',
44	},
45	} as const;
46
47	export type FeatureFlagKey = keyof typeof FeatureFlags;
48	```
49
50	### Step 4: Implement Flag Check Utility
51
52	```typescript
53	// utils/feature-flags.ts
54	export function isFeatureEnabled(
55	flagKey: FeatureFlagKey,
56	context?: { userId?: string; orgId?: string }
57	): boolean {
58	const envValue = process.env[flagKey];
59	if (envValue !== undefined) {
60	return envValue === 'true' \|\| envValue === '1';
61	}
62	return FeatureFlags[flagKey].defaultValue;
63	}
64	```
65
66	### Step 5: Gate the Feature in Code
67
68	```typescript
69	// In handler/service:
70	if (isFeatureEnabled('FEATURE_ORDERS_ASYNC_PROCESSING', { userId })) {
71	await processOrderAsync(order);
72	} else {
73	await processOrderSync(order);
74	}
75	```
76
77	### Step 6: Add to Environment Config
78	- [ ] Add flag to `.env.example` with `false` default
79	- [ ] Add to staging `.env` with `true` for testing
80	- [ ] Keep production as `false` until ready for rollout
81
82	### Step 7: Add Tests for Both Paths
83	- [ ] Test with flag enabled
84	- [ ] Test with flag disabled
85	- [ ] Test flag default behavior (env var not set)
86
87	```typescript
88	describe('when FEATURE_ORDERS_ASYNC_PROCESSING is enabled', () => {
89	beforeEach(() => { process.env.FEATURE_ORDERS_ASYNC_PROCESSING = 'true'; });
90	afterEach(() => { delete process.env.FEATURE_ORDERS_ASYNC_PROCESSING; });
91
92	it('should process order asynchronously', async () => { /* ... */ });
93	});
94
95	describe('when FEATURE_ORDERS_ASYNC_PROCESSING is disabled', () => {
96	it('should process order synchronously', async () => { /* ... */ });
97	});
98	```
99
100	### Step 8: Document Rollout Plan
101	```markdown
102	## Rollout Plan: FEATURE_ORDERS_ASYNC_PROCESSING
103	1. Dev/Staging: Enable, run integration tests
104	2. Canary (5%): Monitor error rate and latency for 24h
105	3. Gradual (25% → 50% → 100%): Each stage monitored for 48h
106	4. Cleanup: Remove flag after 2 weeks at 100%
107	```
108
109	## Flag Cleanup Workflow
110
111	### When to Clean Up
112	- Flag has been at 100% for 2+ weeks
113	- No incidents related to the feature
114	- Target cleanup date reached
115
116	### Cleanup Steps
117	1. Remove the flag check — keep the "enabled" code path
118	2. Remove the "disabled" code path
119	3. Remove flag from `FeatureFlags` config
120	4. Remove from `.env` files
121	5. Remove flag-specific tests (keep the feature tests)
122	6. Update documentation
123
124	## Rules
125	- ALWAYS default new flags to `false` (off)
126	- ALWAYS set a cleanup target date when creating a flag
127	- ALWAYS test both code paths (enabled and disabled)
128	- NEVER nest feature flags (flag inside flag)
129	- NEVER use feature flags for permanent configuration — use config instead
130	- Flag names must be descriptive and follow `FEATURE_DOMAIN_DESCRIPTION` pattern
131	- Maximum 15 active flags at any time — clean up before adding more
132
133	## Completion
134	Feature flag created with config, utility function, code gating, tests, and rollout plan. Cleanup date documented.
135
136	## If a Step Fails
137	- Too many active flags: Audit and clean up stale flags first
138	- Complex branching: Consider a feature flag service (LaunchDarkly, Unleash) instead of env vars
139	- Tests flaky with flag: Ensure env var cleanup in `afterEach`
140	- Can't determine rollout strategy: Default to boolean toggle, upgrade later

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6 picks

Type