Capturing Events

Provider-agnostic event capture system for PAX's Continuous Feedback Loop. Abstracts workspace signals into standardized events, stores them locally, and enables pattern detection for skill evolution.

When to Use

• Running in background during development sessions
• Capturing workspace signals for pattern analysis
• Building episodic memory for skill recommendations
• Supporting assistant-agnostic feedback loops

Architecture

This skill uses a facade pattern (similar to [[pull-request-tool]]) to delegate to provider-specific adapters:

capture-events (facade)
├── universal-provider (default)
│   ├── File watchers
│   ├── Terminal output parser
│   └── Diagnostic collectors
├── copilot-provider
│   ├── Extension integration
│   └── Copilot-specific context
├── codex-provider
│   └── API-based event capture
└── cursor-provider
    └── Extension integration

Provider Selection

The skill auto-detects the environment and selects the appropriate provider:

1. Check for Copilot extension context → use copilot-provider
2. Check for Cursor extension context → use cursor-provider
3. Check for Codex API availability → use codex-provider
4. Default → use universal-provider (workspace-only signals)

Event Schema

All providers emit events following this standardized schema:

{
  "timestamp": "2026-02-26T14:32:00.000Z",
  "provider": "copilot|codex|cursor|universal",
  "event_type": "file_modified|terminal_command|diagnostic|skill_invoked|chat_context",
  "metadata": {
    "file_path": "optional string",
    "command": "optional string",
    "skill_name": "optional string",
    "diff_hash": "optional string (cheap deduplication)",
    "execution_result": "optional success|failure",
    "context_window": "optional array of related events"
  },
  "session_id": "auto-generated or provider-specific"
}

Supported Event Types

Event Type	Trigger	Metadata Fields
file_modified	File created, edited, or deleted	file_path, diff_hash, modification_type
terminal_command	Command executed in terminal	command, execution_result, exit_code
diagnostic	Linter/compiler error or warning	file_path, severity, message
skill_invoked	Agent invokes a skill	skill_name, parameters, execution_result
chat_context	Chat session context change	context_window, user_intent

Storage Location

Events are stored locally in .vscode/pax-memory/ (git-ignored):

.vscode/pax-memory/
├── episodes.jsonl    # Raw events (append-only)
├── patterns.json     # Aggregated patterns
├── signals.json      # Evolving signal definitions
└── proposals/        # Pending recommendations

Usage

Background Mode (Continuous Capture)

Automatic启动 via VS Code Extension:

The capture system runs continuously in the background when enabled in workspace settings:

{
  "pax.feedbackLoop.enabled": true,
  "pax.feedbackLoop.provider": "universal|copilot|codex|cursor",
  "pax.feedbackLoop.captureEvents": true
}

Manual Control:

# Start capture (background process)
capture-events --start --provider universal

# Stop capture
capture-events --stop

# Check status
capture-events --status

On-Demand Capture (Session-Based)

# Capture only during specific session
capture-events --session "work-item-007-implementation" --duration 3600

# Capture with custom filter
capture-events --filter "file_modified,terminal_command" --exclude-pattern "node_modules"

Provider-Specific Usage

Universal Provider (default, no assistant required):

# Uses file watchers and terminal parsing only
capture-events --provider universal

Copilot Provider:

# Requires Copilot extension, captures Copilot-specific context
capture-events --provider copilot

Codex Provider:

# Requires Codex API access
capture-events --provider codex --api-key $CODEX_API_KEY

Cursor Provider:

# Requires Cursor extension
capture-events --provider cursor

Configuration

Workspace Settings (.vscode/settings.json):

{
  "pax.feedbackLoop.capture.enabled": true,
  "pax.feedbackLoop.capture.provider": "universal",
  "pax.feedbackLoop.capture.eventTypes": [
    "file_modified",
    "terminal_command",
    "diagnostic",
    "skill_invoked"
  ],
  "pax.feedbackLoop.capture.excludePatterns": [
    "node_modules/**",
    "**/.git/**",
    "**/dist/**",
    "**/.vscode/**"
  ],
  "pax.feedbackLoop.capture.maxEventsPerSession": 1000,
  "pax.feedbackLoop.capture.sessionIdleMinutes": 30
}

Provider Capabilities

Feature	Universal	Copilot	Codex	Cursor
File modifications	✅	✅	✅	✅
Terminal commands	✅	✅	✅	✅
Diagnostics	✅	✅	✅	✅
Skill invocations	⚠️ limited	✅	✅	✅
Chat context	❌	✅	✅	✅
Session continuity	⚠️ local	✅	✅	✅
Cost	Free	Free	API	Free

Legend: ✅ Full support, ⚠️ Limited support, ❌ Not available

Output Format

Success (append to episodes.jsonl):

{"timestamp":"2026-02-26T14:32:00.000Z","provider":"universal","event_type":"file_modified","metadata":{"file_path":"backlog/007_ast_renderer.md","diff_hash":"abc123","modification_type":"edit"},"session_id":"session-2026-02-26-001"}
{"timestamp":"2026-02-26T14:33:15.000Z","provider":"universal","event_type":"terminal_command","metadata":{"command":"pnpm run lint","execution_result":"success","exit_code":0},"session_id":"session-2026-02-26-001"}

Error Handling:

{
  "status": "error",
  "error_type": "provider_unavailable",
  "message": "Copilot provider requested but extension not detected",
  "fallback": "universal",
  "action": "Switched to universal provider automatically"
}

Integration with Continuous Feedback Loop

This skill is the Capture Layer in PAX's Continuous Feedback Loop architecture:

1. Capture (this skill) → Emit standardized events
2. Memory (background storage) → Append to episodes.jsonl
3. Analyze (background scheduler) → Detect patterns
4. Recommend ([[creating-skill]]) → Generate proposals
5. Promote (human approval) → Invoke [[skill-creator]]

See docs/architecture/continuous-feedback-loop.md for full integration details.

Security & Privacy

• Local-only storage: All events stay in .vscode/pax-memory/ (git-ignored)
• No network calls: Universal provider operates entirely offline
• Opt-in providers: Codex/Copilot/Cursor providers require explicit enablement
• Sensitive data filtering: Automatically excludes secrets, tokens, credentials
• User-controlled: Can be paused, cleared, or disabled at any time

Performance Considerations

• Append-only writes: O(1) event storage using JSONL
• Non-blocking capture: Fire-and-forget pattern, no main thread blocking
• Memory limits: Auto-truncate old episodes when max_events exceeded
• Diff hashing: Cheap deduplication using content-based hashing
• Exclude patterns: Skip noisy directories (node_modules, .git, dist)

Best Practices

1. Use universal provider by default: Works everywhere, no dependencies
2. Enable provider-specific features when available: Richer context from Copilot/Codex/Cursor
3. Configure exclude patterns: Reduce noise from build artifacts and dependencies
4. Monitor storage size: Periodically check .vscode/pax-memory/ size
5. Review proposals regularly: Feedback loop value increases with human validation

Troubleshooting

Event capture not working:

# Check status
capture-events --status

# Verify provider availability
capture-events --check-providers

# Enable debug logging
capture-events --debug --log-file .vscode/pax-memory/debug.log

Too many events:

{
  "pax.feedbackLoop.capture.excludePatterns": [
    "node_modules/**",
    "**/*.log",
    "**/coverage/**"
  ],
  "pax.feedbackLoop.capture.eventTypes": ["file_modified", "skill_invoked"]
}

Provider fallback loop:

If a provider is unavailable, the skill automatically falls back to universal. Check logs for fallback reasons.

Related Skills

• [[creating-skill]] - Consumes captured events to generate skill recommendations
• [[skill-reviewer]] - Evaluates existing skills using pattern data
• [[pull-request-tool]] - Similar facade pattern for PR management

Related Documentation

• Continuous Feedback Loop Architecture
• Skill Composition
• Aspects

Reference vs. Canonical

This skill is PAX-canonical. The auto-evolution reference implementation in pax/evolution/ uses shell-based hooks specific to Claude Code. This skill provides an assistant-agnostic alternative aligned with PAX's design principles.