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Build Log — February 11, 2026

Build Log — February 11, 2026

Context / Focus for Today

RAG evolution day: the AI Coach's memory system went from v1 to v4 in a single day — conversation-aware embeddings, hybrid BM25+semantic search, Cohere reranking, and adaptive retrieval. Major codebase cleanup continued with dead code deletion and deprecated field removal. AI Coach got goal pace integration via a new update_training_zones tool. Sleep metrics got a visual upgrade.


Things I Got Done Today

AI Coach RAG: Cross-Conversation Memory (PR #320)

The AI Coach now remembers previous conversations. RAG v1 laid the foundation — an embedding and retrieval pipeline that gives the coach access to past user interactions.

  • Cross-conversation memory via retrieval-augmented generation
  • Coach can recall context from previous sessions with the user
  • Foundational pipeline for all subsequent RAG improvements

RAG v2 — Conversation-Aware Paired Embeddings

Rather than embedding messages in isolation, v2 pairs user messages with assistant responses as contextual units. This preserves the conversational flow and dramatically improves retrieval relevance.

RAG v3 — Hybrid Search with Temporal Decay (PR #322)

Combines BM25 keyword matching with semantic vector search. Temporal decay means recent conversations rank higher — the coach remembers last week's discussion more vividly than last month's, just like a human would.

  • BM25 catches exact terms users reference ("my 5K last Saturday")
  • Semantic search catches meaning ("how did my long run go")
  • Temporal decay keeps context fresh without forgetting

RAG v4 — Adaptive Retrieval & Cohere Reranking

The final evolution: adaptive retrieval adjusts strategy based on query characteristics, and Cohere reranking re-scores retrieved chunks for precision. Observability hooks track retrieval quality and latency.

  • Adaptive strategy selection based on query type
  • Cohere reranker evaluates query-document pairs holistically
  • Monitoring for retrieval quality in production

AI Coach: Goal Pace Integration

New update_training_zones tool lets the coach update training zones when goal paces change. Zone mismatch detection identifies when current zones don't match stated goals — the coach can proactively fix the disconnect.

Sleep Stage Percentages

Daily metrics cards now show sleep stage percentages — deep, light, REM, and awake time at a glance. Chart axis visibility improved for better readability.

Codebase Cleanup

The cleanup momentum continues:

  • Over 5,500 lines of dead code, one-off scripts, and debug pages removed
  • 8 unused analytics tracking functions deleted
  • Deprecated garmin/gcal field fallbacks removed in favor of platform_sync_state
  • Learned preferences wired up, orphaned routes deleted

Bug Fixes

  • Coach client pointed to v2 endpoint after legacy route deletion
  • Actual AI provider errors surfaced instead of generic "check API configuration"
  • Zwift sync fix, Mission Control activity realtime fix, coach workout display fix

Admin Impersonation

Admin impersonation with read-only safeguards — debug user issues without modifying their data.


Commits Today

  • 22 commits across RAG, AI Coach, cleanup, and bug fixes
  • 5 PRs merged: #320 (RAG v1), #322 (RAG v3 hybrid search), #314 (Zwift sync), #312 (coach display), #311 (MC realtime)
  • Features: RAG v1→v4 pipeline, update_training_zones tool, sleep stage percentages, admin impersonation
  • Refactor: 5,500+ lines of dead code removed, deprecated field fallbacks cleared
  • Fixes: Coach routing, AI error messages, Zwift sync, chart visibility

Notes / Observations

  • The RAG v1→v4 progression in a single day is the highlight. Each version built on the last: basic embeddings → paired conversational context → hybrid BM25+semantic search → adaptive retrieval with Cohere reranking. The AI Coach now has genuine long-term memory.
  • Hybrid search is the right architecture — semantic search alone misses exact terms, BM25 alone misses meaning. Combining both with temporal decay models how human memory actually works: recent context is vivid, older context is accessible but faded.
  • The update_training_zones tool with zone mismatch detection pairs naturally with yesterday's goal-derived pace work. Set a goal → zones update → workouts use correct paces → export to watch. End-to-end.
  • Another 5,500+ lines removed. The codebase has shed over 12,000 lines of dead code in two days while adding significant new capabilities.

Momentum Score: 9 / 10

Exceptional day anchored by the RAG v1→v4 evolution. The AI Coach went from having no cross-conversation memory to an adaptive, reranked hybrid search pipeline — in one day. The update_training_zones tool adds another proactive capability. Sleep metrics and admin impersonation round out the features. 22 commits, 5 PRs, 5,500+ lines cleaned up. The project is building intelligence and shedding weight simultaneously.