feat(platform): add the metamask-extension overlay for feature-flags

.github/CODEOWNERS

@@ -17,6 +17,7 @@
 /domains/coding/         @MetaMask/extension-platform @MetaMask/mobile-platform @MetaMask/core-platform
 /domains/general/        @MetaMask/extension-platform @MetaMask/mobile-platform
 /domains/performance/    @MetaMask/extension-platform @MetaMask/mobile-platform
+/domains/platform/       @MetaMask/extension-platform @MetaMask/mobile-platform @MetaMask/core-platform
 /domains/perps/          @MetaMask/perps
 /domains/pr-workflow/    @MetaMask/extension-platform @MetaMask/mobile-platform
 /domains/swaps/          @MetaMask/swaps-engineers

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `feature-flags` skill with a repo-agnostic base and a MetaMask Mobile overlay for version-gated remote flags. Marked `base: true` so it installs even when its domain is filtered out. ([#147](https://github.com/MetaMask/skills/pull/147))
+- Add `analytics` skill (`platform/analytics`, moved from `coding`) with a repo-agnostic base and a MetaMask Mobile overlay for the canonical tracking API. Marked `base: true` so it installs even when its domain is filtered out. ([#140](https://github.com/MetaMask/skills/pull/140))
+
 ## [0.3.1]
 
 ### Fixed

README.md

@@ -143,6 +143,7 @@ tools/
 | -------------- | ----------------- | ------------------------------------------- |
 | `web3-tools`   | dApp builders     | `gator-cli`, `smart-accounts-kit`, `oh-my-opencode` |
 | `coding`       | MM product eng    | Coding guidelines, controller patterns       |
+| `platform`     | MM product eng    | Product analytics and other platform skills  |
 | `agentic`      | MM product eng    | Experimental recipe workflows and runtime proof tools |
 | `assets`       | MM product eng    | Assets domain skills |
 | `general`      | All agents        | `codex`, `gemini` CLI usage guides           |
@@ -386,6 +387,12 @@ Extra metadata blocks (e.g. OpenClaw-style `metadata:` with emoji and
 homepage) are preserved through install — only `name`, `description`,
 `maturity`, `base`, and `scope` are read by the CLI.
 
+`base: true` installs the skill even when its domain is filtered out.
+`--exclude` / `SKILLS_EXCLUDE` still wins. The maturity filter runs before the
+base bypass, so `--maturity stable` drops a `base: true` experimental skill.
+A skill with a `repos/` directory and no overlay for `--repo` is skipped
+(this `analytics` skill installs for Mobile and is skipped for Extension).
+
 The 1,536-character ceiling is a repo budget rather than an operator limit — the
 description is always-on context for every installed skill, so it is capped
 deliberately. It is enforced by `yarn audit:skills` from

domains/platform/skills/analytics/repos/metamask-mobile.md

@@ -0,0 +1,194 @@
+---
+repo: metamask-mobile
+parent: analytics
+---
+
+# Analytics — MetaMask Mobile
+
+Human-facing file map: `app/core/Analytics/README.md`. A/B enrichment SSOT: `docs/ab-testing.md`.
+
+## Canonical API
+
+| Role | Path |
+|------|------|
+| Helper (non-React) | `app/util/analytics/analytics.ts` → `analytics.trackEvent` |
+| Helper (UI) | `app/components/hooks/useAnalytics/useAnalytics.ts` → `useAnalytics` |
+| Engine (controllers) | `app/core/Engine/utils/analytics.ts` → `trackEvent`, `buildAndTrackEvent` |
+| Event builder | `app/util/analytics/AnalyticsEventBuilder.ts` → `AnalyticsEventBuilder.createEventBuilder` |
+| Catalog | `app/core/Analytics/` → `MetaMetricsEvents` at call sites; `EVENT_NAME` in catalog modules |
+| Typed helpers | `app/util/analytics/actionButtonTracking.ts` (sibling files matching `*Tracking.ts`) |
+| A/B registry | `app/util/analytics/abTestAnalyticsRegistry.ts` (feature-local `abTestConfig.ts`, e.g. `app/components/Views/Homepage/abTestConfig.ts`) |
+| Test factory | `app/util/test/analyticsMock.ts` → `createMockUseAnalyticsHook` (default); `createMockEventBuilder` (optional standalone double) |
+
+`useAnalytics()` returns `trackEvent`, `createEventBuilder`, `identify`, `enable`,
+`isEnabled`, `getAnalyticsId`, and data-deletion helpers.
+
+Controllers that already talk to Engine import `trackEvent` / `buildAndTrackEvent`
+from `app/core/Engine/utils/analytics.ts`. Those helpers always wrap the
+messenger call in try/catch. `enrichWithABTests` runs only when the event name
+is registered in `app/util/analytics/abTestAnalyticsRegistry.ts` (fed by
+feature-local `abTestConfig.ts`). New experiment events: follow
+`docs/ab-testing.md`. Do not copy Engine-util internals.
+
+`createMockEventBuilder()` default `build()` is
+`{ name: 'mock-event', properties: {}, sensitiveProperties: {} }`. Use it only
+as a standalone builder double, wrapped in `jest.fn(() => createMockEventBuilder())`.
+
+## Requirements
+
+- UI: platform `useAnalytics` from `app/components/hooks/useAnalytics/useAnalytics.ts`
+- Non-React: `analytics.trackEvent`
+- Controllers: `trackEvent` / `buildAndTrackEvent` from `app/core/Engine/utils/analytics.ts`
+- When a typed helper exists in `app/util/analytics/` (files matching `*Tracking.ts`) for this event, call it
+- Call sites (new and existing) import `MetaMetricsEvents.*`. Register new names as `EVENT_NAME` + `generateOpt` in catalog modules, then emit via `MetaMetricsEvents`. Reuse a catalog name only when this control is the same interaction as existing call sites (same event, same product meaning).
+- Properties via `.addProperties(...).build()`
+- UI tests: `createMockUseAnalyticsHook` wrapping `useAnalytics`, including when the file already mocks the hook. Default: `createMockUseAnalyticsHook({ trackEvent: mockTrackEvent })`. Tests that assert `addProperties` keep `AnalyticsEventBuilder.createEventBuilder`
+- Non-React tests: assert `AnalyticsEventBuilder.createEventBuilder` and `analytics.trackEvent` or Engine `trackEvent` / `buildAndTrackEvent`
+
+Generic UI (`app/components/UI/BalanceEmptyState/BalanceEmptyState.tsx`):
+
+```ts
+import React from 'react';
+import { MetaMetricsEvents } from '../../../core/Analytics';
+import { useAnalytics } from '../../hooks/useAnalytics/useAnalytics';
+
+const BalanceEmptyState: React.FC<BalanceEmptyStateProps> = ({
+  testID = 'balance-empty-state',
+  ...props
+}) => {
+  const { trackEvent, createEventBuilder } = useAnalytics();
+
+  const handleAction = () => {
+    trackEvent(
+      createEventBuilder(MetaMetricsEvents.RAMPS_BUTTON_CLICKED)
+        .addProperties({
+          button_text: 'Add funds',
+          location: 'BalanceEmptyState',
+          ramp_type: 'UNIFIED_BUY_2',
+        })
+        .build(),
+    );
+  };
+```
+
+Typed helper (`app/components/Views/Homepage/components/HomepageActionButtonsGrid/buttons/SendButton.tsx`):
+
+```ts
+import React, { useCallback } from 'react';
+import { useAnalytics } from '../../../../../hooks/useAnalytics/useAnalytics';
+import {
+  ActionButtonType,
+  ActionLocation,
+  trackActionButtonClick,
+} from '../../../../../../util/analytics/actionButtonTracking';
+
+const SendButton = ({
+  actionPosition,
+  allowTwoLineLabel,
+  onSend,
+}: SendButtonProps) => {
+  const { trackEvent, createEventBuilder } = useAnalytics();
+
+  const handlePress = useCallback(() => {
+    trackActionButtonClick(trackEvent, createEventBuilder, {
+      action_name: ActionButtonType.SEND,
+      action_position: actionPosition,
+      button_label: label,
+      location: ActionLocation.HOME,
+    });
+    onSend();
+  }, [actionPosition, createEventBuilder, label, onSend, trackEvent]);
+```
+
+Non-React (`app/util/analytics/accountAccessTracking.ts`):
+
+```ts
+import { MetaMetricsEvents } from '../../core/Analytics/MetaMetrics.events';
+import { analytics } from './analytics';
+import { AnalyticsEventBuilder } from './AnalyticsEventBuilder';
+
+analytics.trackEvent(
+  AnalyticsEventBuilder.createEventBuilder(
+    MetaMetricsEvents.APP_UNLOCKED_FAILED,
+  )
+    .addProperties({
+      unlock_error_type: unlockErrorType,
+      forced_reset: forcedReset,
+    })
+    .build(),
+);
+```
+
+Controllers:
+
+```ts
+import { buildAndTrackEvent } from '../../core/Engine/utils/analytics';
+import { MetaMetricsEvents } from '../../core/Analytics';
+
+buildAndTrackEvent(
+  initMessenger,
+  MetaMetricsEvents.PROFILE_ACTIVITY_UPDATED.category,
+  {
+    profile_id: profileId,
+    feature_name: 'Contacts Sync',
+    action: 'Contacts Sync Contact Updated',
+  },
+);
+```
+
+`createEventBuilder` copies only `category` from `IMetaMetricsEvent`. When
+migrating a wrapper that used `generateOpt(name, action, description)`, re-apply
+`properties.action` and `properties.name` with `addProperties`.
+
+`generateOpt` belongs in catalog modules: `app/core/Analytics/MetaMetrics.events.ts`,
+`app/core/Analytics/events/`, and feature-local `<feature>/analytics/events.ts`
+(see SampleFeature). Component files import catalog entries; they do not call
+`generateOpt` themselves.
+
+Tests mock the hook with the factory, not a hand-built object.
+Call `createMockUseAnalyticsHook` again in `beforeEach` after
+`jest.resetAllMocks()` — that wipes mock implementations. `jest.clearAllMocks()`
+does not.
+
+```ts
+import { useAnalytics } from '../../hooks/useAnalytics/useAnalytics';
+import { createMockUseAnalyticsHook } from '../../../util/test/analyticsMock';
+
+jest.mock('../../hooks/useAnalytics/useAnalytics');
+
+beforeEach(() => {
+  jest.resetAllMocks();
+  jest.mocked(useAnalytics).mockReturnValue(
+    createMockUseAnalyticsHook({
+      trackEvent: mockTrackEvent,
+    }),
+  );
+});
+```
+
+Standalone builder double (only when the test needs one):
+
+```ts
+createEventBuilder: jest.fn(() => createMockEventBuilder()),
+```
+
+## Reject
+
+- `addSensitiveProperties` on new tracking. Existing call sites: drop those
+  fields only. Moving the last sensitive field into `addProperties` flips
+  `isAnonymous` (true iff `sensitiveProperties` is nonempty). Do not relocate
+  without human sign-off.
+- A new feature-local tracker that is not a file matching `*Tracking.ts` under
+  `app/util/analytics/`, a feature-local `abTestConfig.ts`, or a catalog
+  `generateOpt` module (`app/core/Analytics/MetaMetrics.events.ts`,
+  `app/core/Analytics/events/`, `<feature>/analytics/events.ts`)
+- Replacing `MetaMetricsEvents.*` at a call site with `EVENT_NAME.*`
+- Reintroducing `useMetrics` (removed) or MetaMetrics internals at call sites
+- Dropping `generateOpt` `action` / `name` when migrating `IMetaMetricsEvent` call sites (until the catalog migration lands)
+- Hand-built `useAnalytics` mock objects — use `createMockUseAnalyticsHook`
+- Raw `initMessenger.call('AnalyticsController:trackEvent', …)` when Engine
+  `trackEvent` / `buildAndTrackEvent` is available
+- Defaulting UI tests to `createEventBuilder: jest.fn(() => createMockEventBuilder())`
+  when `createMockUseAnalyticsHook()` already stubs the builder
+- Attaching a new control to a catalog event whose live call sites are a different product (example: `VIEW_ALL_ASSETS_CLICKED` is wallet tokens/NFTs `asset_type`, not a homepage section)
+- Firing an existing catalog event at a new lifecycle (example: `TOKEN_DETECTED` on controller init). Add a catalog name for that lifecycle.

domains/platform/skills/analytics/skill.md

@@ -0,0 +1,25 @@
+---
+name: analytics
+description: >-
+  Product analytics and event tracking. Use when adding, migrating, or
+  reviewing tracked events, or when writing tests for analytics call sites.
+maturity: stable
+base: true
+---
+
+# Analytics
+
+Use this skill for product event tracking.
+
+## When to use
+
+- Adding or migrating event tracking in UI or non-UI code
+- Writing or updating tests for analytics call sites
+- Reviewing a PR that introduces or changes tracked events
+
+## Workflow
+
+1. Register this interaction in the catalog (`EVENT_NAME` + `generateOpt` in catalog modules). Reuse an existing catalog name only when this control is another instance of that same interaction (same dashboard event, same owners).
+2. Attach properties on the event builder.
+3. Send the built event through the tracking entry point.
+4. In UI tests, wrap `useAnalytics` with the test factory (including files that already mock the hook). In non-React tests, assert the builder and the helper or Engine tracking util.