feat(features): per-feature freshness spec — JIT vs batched (#61)

Each ml/features/*.py now declares freshness, source, and fallback per
feature. ProfileFeature gains ttl_sec (mirrored from registry.ts),
freshness="batched", source, and fallback. context.py adds
ContextFeatureSpec + CONTEXT_FEATURES for the three JIT features
(hour_of_day, day_of_week, tasks). CI test parses ttlSec from registry.ts
to catch drift. ml/README updated with split JIT/batched feature contract.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-04-25 17:02:55 +00:00
parent bd3ea1b8b1
commit 45416000f9
6 changed files with 218 additions and 21 deletions

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@@ -5,7 +5,7 @@ Python. Owns models, features, training, online scoring.
| Dir | Role | Phase |
|---|---|---|
| `serving/` | FastAPI online scorer (`/score`, `/generate`) + LiteLLM gateway + prompt registry (`prompts.py`) + JetStream consumers for `signals.>` / `feedback.>`, called by `recommender` | 12 |
| `features/` | context assembler (`context.py`): signals → `PromptContext`; Feast adapter later | 2 |
| `features/` | context assembler (`context.py`): signals → `PromptContext`; profile-feature schema mirror (`profile_schema.py`); Feast adapter later | 2 |
| `pipelines/` | batch feature + training DAGs (Prefect/Airflow) | 4 |
| `registry/` | MLflow-backed model registry integration | 4 |
| `experiments/` | A/B assignment + multi-armed bandit policies | 4 |
@@ -18,14 +18,24 @@ Python. Owns models, features, training, online scoring.
- Training reads from the offline feature store; serving reads from the online feature store; definitions are shared (no train/serve skew).
- Shadow deploys before any policy change that affects real users.
## Profile-feature contract
## Feature contract
### Profile features (batched)
User-level features (completion rate, preferred hour, tip volume…) are computed
by the TypeScript recommender and shipped to ml/serving on every `/score` and
by the TypeScript recommender and shipped to `ml/serving` on every `/score` and
`/generate` call as `profile_features: dict | None`. The Python mirror in
`features/profile_schema.py` documents the available names + dtypes — keep it
in sync with `services/api/src/profile/registry.ts` (a CI-style test asserts
the name sets match). See ADR-0011.
`features/profile_schema.py` documents each feature's name, dtype, TTL, source,
and null fallback — keep it in sync with `services/api/src/profile/registry.ts`
(a CI-style test asserts names and `ttlSec` values match). See ADR-0011.
### Context features (JIT)
Request-time signals assembled by `features/context.py` (`hour_of_day`,
`day_of_week`, task list). These are never cached — they are derived from the
system clock and the live Todoist feed at the moment of the score call.
`CONTEXT_FEATURES` in `context.py` declares freshness, source, and fallback for
each field (issue #61).
## Prompt registry