[Part 3/6] feat(telemetry): enhance metrics with performance monitoring APIs

[eLyiN]

Summary

Enhances the telemetry metrics system with 12 new performance monitoring metrics, advanced recording functions, and performance monitoring configuration. This provides comprehensive instrumentation for startup timing, memory usage, CPU tracking, and performance analysis.

Dependencies

⚠️ This PR depends on:

• [Part 1/6] feat(telemetry): add rate limiter and high-water mark tracker with tests #8110 - Part 1: Telemetry Primitives (RateLimiter, HighWaterMarkTracker)
• [Part 2/6] feat(telemetry): add activity detector with user interaction tracking #8111 - Part 2: Activity Detection (ActivityDetector, isUserActive)

Review Order: Please review Parts 1-2 first (#8110, #8111), then this PR.

Related PRs - Enhanced Performance Monitoring Split

This is Part 3 of 6 in the split implementation of #2127:

• ✅ Part 1/6: [Part 1/6] feat(telemetry): add rate limiter and high-water mark tracker with tests #8110 (telemetry-primitives) - Foundation
• ✅ Part 2/6: [Part 2/6] feat(telemetry): add activity detector with user interaction tracking #8111 (activity-detector) - Activity tracking
• ✅ Part 3/6: [Part 3/6] feat(telemetry): enhance metrics with performance monitoring APIs #8113 (metrics-enhancements) - YOU ARE HERE
• ⏳ Part 4/6: [Part 4/6] feat(telemetry): add memory monitor with activity-aware recording and tests #8122 (memory-monitor) - depends on Parts 1-3
• ⏳ Part 5/6: [Part 5/6] feat(telemetry): add activity monitor with event-driven snapshots #8124 (activity-monitor) - depends on Parts 1-4
• ⏳ Part 6/6: [Part 6/6] feat(cli): add activity monitoring hooks and integrate telemetry documentation #8125 (cli-integration) - depends on Parts 1-5
• 📋 Tracking Issue: [Split PRs] Enhanced Performance Monitoring Implementation - Split into 6 reviewable PRs #8120

Changes in This PR

Performance Metrics Constants (packages/core/src/telemetry/constants.ts)

Adds 12 new OpenTelemetry-compliant metric constants for comprehensive performance monitoring including startup timing, memory usage, CPU tracking, tool execution analysis, and performance regression detection.

Enhanced Metrics Recording (packages/core/src/telemetry/metrics.ts)

New Performance Recording Functions: 12 new functions covering startup performance, resource monitoring, tool execution analysis, API performance tracking, and performance analysis with rich attribution and OpenTelemetry integration.

---

Next Steps: After Parts 1-3 merge, Parts 4-6 will add memory monitoring, activity monitoring, and CLI integration using these enhanced metrics.

[gemini-code-assist]

Summary of Changes

Hello @eLyiN, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the existing telemetry system by integrating a robust performance monitoring framework. The primary goal is to capture and analyze various performance aspects of the application, such as startup times, resource utilization, and the efficiency of tool and API interactions. This foundational work provides the necessary instrumentation to identify performance bottlenecks and track improvements over time, without affecting runtime behavior unless explicitly enabled.

Highlights

• Expanded Telemetry Metrics: Introduced comprehensive performance monitoring primitives including startup duration, memory/CPU usage, tool queue depth, and execution breakdowns.
• New API Metrics: Added metrics for token efficiency, API request breakdowns, and performance scoring to provide deeper insights into API interactions.
• Monitoring Utilities: Implemented utilities for regression/baseline recording and checks for performance monitoring state.
• Performance-Related Constants: Incorporated new constants to ensure consistent thresholds and naming conventions for performance metrics.
• Exported APIs and Enums: Exposed new performance metrics APIs and enums from the telemetry index for external use.
• Inert Functions: Ensured that all new performance monitoring functions are inert unless explicitly called and guarded by isPerformanceMonitoringActive.

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[gemini-code-assist]

Code Review

This pull request significantly enhances telemetry by adding a comprehensive suite of performance monitoring metrics. The implementation is robust, with new constants, metric functions, and thorough unit tests. I have a couple of suggestions to improve the maintainability and consistency of the new metric collection logic, primarily around simplifying memory usage tracking and ensuring consistent attributes for baseline comparison metrics. Overall, this is a great addition for performance analysis.

[joshualitt]

@eLyiN , this PR looks basically ready to go once the comments from Gemini are addressed. Please take a look, we'd love to land this ASAP.

[eLyiN]

@eLyiN , this PR looks basically ready to go once the comments from Gemini are addressed. Please take a look, we'd love to land this ASAP.

Hi @joshualitt , sorry didn't have much time this week, rebasing and solving conflicts now, will take a look on the weekend

[eLyiN]

/gemini review

[gemini-code-assist]

Code Review

This pull request significantly enhances the telemetry system by adding a comprehensive set of performance monitoring metrics. The changes include new metric constants, OpenTelemetry instruments, and recording functions for tracking startup time, resource usage, and other performance-related aspects. The implementation is well-structured, and it's accompanied by a thorough suite of tests covering various scenarios, including edge cases like zero baseline values.

My review focuses on ensuring the new telemetry code adheres to best practices for library development. I have one suggestion to improve logging consistency and prevent potential side effects for consumers of this package.

[jacob314]

[eLyiN]

@joshualitt, The conflicts have been resolved and it's ready to be merged, in my opinion. Thank you!