Copilot instructions

1---
2description: Use when asked to work on telemetry events
3---
4 
5Patterns for GDPR-compliant telemetry in VS Code with proper type safety and privacy protection.
6 
7## Implementation Pattern
8 
9### 1. Define Types
10```typescript
11type MyFeatureEvent = {
12    action: string;
13    duration: number;
14    success: boolean;
15    errorCode?: string;
16};
17 
18type MyFeatureClassification = {
19    action: { classification: 'SystemMetaData'; purpose: 'FeatureInsight'; comment: 'The action performed.' };
20    duration: { classification: 'SystemMetaData'; purpose: 'PerformanceAndHealth'; isMeasurement: true; comment: 'Time in milliseconds.' };
21    success: { classification: 'SystemMetaData'; purpose: 'FeatureInsight'; isMeasurement: true; comment: 'Whether action succeeded.' };
22    errorCode: { classification: 'SystemMetaData'; purpose: 'PerformanceAndHealth'; comment: 'Error code if action failed.' };
23    owner: 'yourGitHubUsername';
24    comment: 'Tracks MyFeature usage and performance.';
25};
26```
27 
28### 2.1. Send Event
29```typescript
30this.telemetryService.publicLog2<MyFeatureEvent, MyFeatureClassification>('myFeatureAction', {
31    action: 'buttonClick',
32    duration: 150,
33    success: true
34});
35```
36 
37### 2.2. Error Events
38For error-specific telemetry with stack traces or error messages:
39```typescript
40type MyErrorEvent = {
41    operation: string;
42    errorMessage: string;
43    duration?: number;
44};
45 
46type MyErrorClassification = {
47    operation: { classification: 'SystemMetaData'; purpose: 'PerformanceAndHealth'; comment: 'The operation that failed.' };
48    errorMessage: { classification: 'CallstackOrException'; purpose: 'PerformanceAndHealth'; comment: 'The error message.' };
49    duration: { classification: 'SystemMetaData'; purpose: 'PerformanceAndHealth'; isMeasurement: true; comment: 'Time until failure.' };
50    owner: 'yourGitHubUsername';
51    comment: 'Tracks MyFeature errors for reliability.';
52};
53 
54this.telemetryService.publicLogError2<MyErrorEvent, MyErrorClassification>('myFeatureError', {
55    operation: 'fileRead',
56    errorMessage: error.message,
57    duration: 1200
58});
59```
60 
61### 3. Service Injection
62```typescript
63constructor(
64    @ITelemetryService private readonly telemetryService: ITelemetryService,
65) { super(); }
66```
67 
68## GDPR Classifications & Purposes
69 
70**Classifications (choose the most restrictive):**
71- `SystemMetaData` - **Most common.** Non-personal system info, user preferences, feature usage, identifiers (extension IDs, language types, counts, durations, success flags)
72- `CallstackOrException` - Error messages, stack traces, exception details. **Only for actual error information.**
73- `PublicNonPersonalData` - Data already publicly available (rare)
74 
75**Purposes (combine with different classifications):**
76- `FeatureInsight` - **Default.** Understanding how features are used, user behavior patterns, feature adoption
77- `PerformanceAndHealth` - **For errors & performance.** Metrics, error rates, performance measurements, diagnostics
78 
79**Required Properties:**
80- `comment` - Clear explanation of what the field contains and why it's collected
81- `owner` - GitHub username (infer from branch or ask)
82- `isMeasurement: true` - **Required** for all numeric values flags used in calculations
83 
84## Error Events
85 
86Use `publicLogError2` for errors with `CallstackOrException` classification:
87 
88```typescript
89this.telemetryService.publicLogError2<ErrorEvent, ErrorClassification>('myFeatureError', {
90	errorMessage: error.message,
91	errorCode: 'MYFEATURE_001',
92	context: 'initialization'
93});
94```
95 
96## Naming & Privacy Rules
97 
98**Naming Conventions:**
99- Event names: `camelCase` with context (`extensionActivationError`, `chatMessageSent`)
100- Property names: specific and descriptive (`agentId` not `id`, `durationMs` not `duration`)
101- Common patterns: `success/hasError/isEnabled`, `sessionId/extensionId`, `type/kind/source`
102 
103**Critical Don'ts:**
104- ❌ No PII (usernames, emails, file paths, content)
105- ❌ Missing `owner` field in classification (infer from branch name or ask user)
106- ❌ Vague comments ("user data" → "selected language identifier")
107- ❌ Wrong classification
108- ❌ Missing `isMeasurement` on numeric metrics
109 
110**Privacy Requirements:**
111- Minimize data collection to essential insights only
112- Use hashes/categories instead of raw values when possible
113- Document clear purpose for each data point
114