diff --git a/docs/adr/0011-user-profile-features.md b/docs/adr/0011-user-profile-features.md
new file mode 100644
index 0000000..cc9e340
--- /dev/null
+++ b/docs/adr/0011-user-profile-features.md
@@ -0,0 +1,82 @@
+# ADR-0011 — User-profile feature registry
+
+**Status:** Accepted (phase A)
+**Date:** 2026-04-25
+**Issue:** #81
+
+## Context
+
+The bandit and LLM tip generator only saw per-candidate features (`is_overdue`,
+`task_age_days`, `priority`) plus contextual time signals. There was no notion
+of a *user-level* profile — completion rate, dismiss rate, preferred hour, tip
+volume — even though all the raw data already lives in `tip_views`,
+`tip_feedback`, and `tip_scores`.
+
+#81 originally proposed putting the feature registry in `ml/features/` (Python).
+We're choosing differently for the data-locality reason: the aggregations are
+SQL queries against tables owned by `services/api`. Computing them in Python
+means a network round-trip per recommendation for queries that are sub-ms in TS.
+
+## Decision
+
+Two-sided design with one source of truth:
+
+- **`services/api/src/profile/registry.ts`** — *source of truth*. Each
+  `FeatureDefinition` declares `{ name, dtype, ttlSec, description, compute }`.
+  `compute(userId, sqlite)` runs the aggregation SQL directly via the raw
+  better-sqlite3 client.
+- **`services/api/src/profile/builder.ts`** — `getProfile(userId)` returns the
+  full feature dict, lazily recomputing any entry whose stored row is past its
+  `ttlSec`. `rebuildProfile(userId)` force-refreshes everything.
+- **`user_profile_features` table** — KV per `(user_id, name)` with `value`
+  (REAL) for numeric and `value_text` (TEXT) for categorical. Phase A
+  ships only numeric features.
+- **`ml/features/profile_schema.py`** — *contract mirror*. Names, dtypes, and
+  descriptions only — no compute. A test reads the TS file and asserts the
+  name sets match, catching drift.
+- **`POST /score` and `POST /generate`** in `ml/serving` accept an optional
+  `profile_features: dict | None`. Stored on the request object but **not
+  consumed by the bandit yet** — extending the feature vector changes `D` and
+  resets every user's learned state. That's a deliberate phase-B decision.
+
+Initial features: `completion_rate_30d`, `dismiss_rate_30d`,
+`mean_dwell_ms_30d`, `preferred_hour`, `tip_volume_30d`.
+
+## Consequences
+
+**Good:**
+- Adding a feature = one entry in `registry.ts` + one mirror line in
+  `profile_schema.py`. No DB migration required (KV table).
+- TTL keeps recommendation latency bounded: every recommend call refreshes at
+  most 5 features, each a single indexed query against an already-warm DB.
+- Profile data is now visible to ml/serving via the request payload — eval
+  harnesses and the LLM tip generator can use it without a DB round-trip.
+
+**Trade-offs:**
+- TS owns compute → ml-side changes that need new features still require a
+  TS PR. Acceptable while the modular monolith holds; if `ml/serving`
+  becomes the system of record for any feature, it should own its own table.
+- TTL-based refresh has up-to-`ttlSec` lag on user-visible behavior change.
+  Phase B replaces this with event-driven incremental updates subscribing to
+  `signals.tip.feedback`.
+
+## Phase B (deferred)
+
+- Subscribe to `signals.tip.feedback` for incremental updates instead of TTL.
+- Extend the bandit feature vector to include profile features (deliberate
+  `D` change with state-migration plan).
+- Admin page: per-user profile view + manual rebuild button.
+- Staleness/data-quality alerts in `/admin/data-quality`.
+
+## Alternatives considered
+
+**Registry in Python (per the original issue text)** — rejected: the
+aggregations live in TS-owned tables; round-tripping per recommend adds
+latency for no architectural gain.
+
+**Compute in the recommender route inline** — rejected: features would be
+recomputed on every recommendation with no cache or staleness semantics.
+
+**Use `tip_scores.featuresJson` as the profile store** — rejected: that
+column is per-tip explainability, not per-user state. Mixing them complicates
+both reads.
diff --git a/ml/README.md b/ml/README.md
index e62659d..a45f15f 100644
--- a/ml/README.md
+++ b/ml/README.md
@@ -18,6 +18,15 @@ 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
+
+User-level features (completion rate, preferred hour, tip volume…) are computed
+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.
+
 ## Prompt registry
 
 `serving/prompts.py` keys tip-generation prompts by stable version string. Adding a new variant means adding an entry — no caller changes. Selection precedence: `POST /generate` body's `prompt_version` field → env `DEFAULT_PROMPT_VERSION` → `"v1"`. The TypeScript recommender drives selection via `TIP_PROMPT_VERSION` (single value or comma-separated rotation); the version actually used flows back in the response and is persisted to `tip_scores.prompt_version` so the admin reward-analytics dashboard can bucket reactions per variant.
diff --git a/ml/features/profile_schema.py b/ml/features/profile_schema.py
new file mode 100644
index 0000000..79e69ad
--- /dev/null
+++ b/ml/features/profile_schema.py
@@ -0,0 +1,53 @@
+"""Profile-feature schema mirror (#81 phase A).
+
+The TypeScript registry in ``services/api/src/profile/registry.ts`` is the
+*source of truth* — features are computed there because the data lives in the
+TS-owned SQLite DB. This module is a documentation/typing mirror so Python
+code (ml/serving, eval harnesses, notebooks) knows what fields to expect on
+``profile_features`` payloads without round-tripping the API.
+
+Update this file whenever you add or rename a feature in the TS registry.
+The accompanying test asserts the two stay in sync at the name level.
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Literal
+
+
+Dtype = Literal["numeric", "categorical"]
+
+
+@dataclass(frozen=True)
+class ProfileFeature:
+    name: str
+    dtype: Dtype
+    description: str
+
+
+PROFILE_FEATURES: tuple[ProfileFeature, ...] = (
+    ProfileFeature(
+        "completion_rate_30d", "numeric",
+        'Fraction of tips served in the last 30 days that received a "done" reaction.',
+    ),
+    ProfileFeature(
+        "dismiss_rate_30d", "numeric",
+        'Fraction of tips served in the last 30 days that received a "dismiss" reaction.',
+    ),
+    ProfileFeature(
+        "mean_dwell_ms_30d", "numeric",
+        "Average dwell time (ms between served and reacted) over the last 30 days.",
+    ),
+    ProfileFeature(
+        "preferred_hour", "numeric",
+        'Hour-of-day with the most "done" reactions in the last 30 days (0-23).',
+    ),
+    ProfileFeature(
+        "tip_volume_30d", "numeric",
+        "Number of tips served to the user in the last 30 days.",
+    ),
+)
+
+
+def feature_names() -> set[str]:
+    return {f.name for f in PROFILE_FEATURES}
diff --git a/ml/features/test_profile_schema.py b/ml/features/test_profile_schema.py
new file mode 100644
index 0000000..06dccaf
--- /dev/null
+++ b/ml/features/test_profile_schema.py
@@ -0,0 +1,41 @@
+"""Smoke test for profile_schema mirror (#81 phase A).
+
+The TS registry in services/api/src/profile/registry.ts is the source of truth.
+This test checks the names listed here match the registry by reading the TS
+file and grepping for `name: '...'`. Crude but cheap, and it catches the
+common rename/add-without-mirror failure mode.
+"""
+from __future__ import annotations
+import re
+from pathlib import Path
+
+from ml.features.profile_schema import PROFILE_FEATURES, feature_names
+
+
+REGISTRY_PATH = Path(__file__).resolve().parents[2] / "services" / "api" / "src" / "profile" / "registry.ts"
+
+
+def _ts_registry_names() -> set[str]:
+    text = REGISTRY_PATH.read_text(encoding="utf-8")
+    # Each FEATURES entry has `name: 'something_30d',`. Extract every match.
+    return set(re.findall(r"name:\s*'([a-zA-Z0-9_]+)'", text))
+
+
+def test_python_mirror_matches_ts_registry():
+    py_names = feature_names()
+    ts_names = _ts_registry_names()
+    assert py_names == ts_names, (
+        f"Profile feature names drifted between TS registry and Python mirror.\n"
+        f"  in Python only: {sorted(py_names - ts_names)}\n"
+        f"  in TS only:     {sorted(ts_names - py_names)}"
+    )
+
+
+def test_profile_schema_no_duplicates():
+    names = [f.name for f in PROFILE_FEATURES]
+    assert len(names) == len(set(names)), f"duplicate names: {names}"
+
+
+def test_profile_schema_dtypes_known():
+    for f in PROFILE_FEATURES:
+        assert f.dtype in {"numeric", "categorical"}
diff --git a/ml/serving/main.py b/ml/serving/main.py
index 2bd9225..4cdb6e5 100644
--- a/ml/serving/main.py
+++ b/ml/serving/main.py
@@ -152,6 +152,11 @@ class ScoreRequest(BaseModel):
     user_id: str
     candidates: list[Candidate]
     context: Context = Context()
+    # User-level features computed by the API (#81 phase A). Accepted, logged,
+    # but not yet consumed by the bandit — extending the feature vector
+    # changes `D` and resets every user's learned state, which is a deliberate
+    # follow-up (phase B), not a side effect of this PR.
+    profile_features: Optional[dict] = None
 
 
 class ScoreResponse(BaseModel):
@@ -184,6 +189,9 @@ class GenerateRequest(BaseModel):
     context: PromptContext = PromptContext()
     n: int = 3
     prompt_version: Optional[str] = None  # None → server default (env DEFAULT_PROMPT_VERSION)
+    # User-level features (#81 phase A). Accepted by the contract; not yet
+    # injected into the prompt — that's a #84-style prompt-design decision.
+    profile_features: Optional[dict] = None
 
 
 class TipCandidate(BaseModel):
diff --git a/services/api/src/db/index.ts b/services/api/src/db/index.ts
index 37fbea2..f22bb4b 100644
--- a/services/api/src/db/index.ts
+++ b/services/api/src/db/index.ts
@@ -100,6 +100,16 @@ export function runMigrations() {
       created_at TEXT NOT NULL
     );
 
+    CREATE TABLE IF NOT EXISTS user_profile_features (
+      user_id TEXT NOT NULL REFERENCES users(id),
+      name TEXT NOT NULL,
+      value REAL,
+      value_text TEXT,
+      updated_at TEXT NOT NULL,
+      ttl_sec INTEGER NOT NULL,
+      PRIMARY KEY (user_id, name)
+    );
+
     CREATE TABLE IF NOT EXISTS sim_runs (
       id TEXT PRIMARY KEY,
       policy_a TEXT NOT NULL,
diff --git a/services/api/src/db/schema.ts b/services/api/src/db/schema.ts
index 3641937..6fd1465 100644
--- a/services/api/src/db/schema.ts
+++ b/services/api/src/db/schema.ts
@@ -87,6 +87,20 @@ export const tipScores = sqliteTable('tip_scores', {
   tipKind: text('tip_kind'),                         // 'task' | 'advice' | 'insight' | 'reminder'
 });
 
+// ── User profile features (#81 phase A) ────────────────────────────────────
+// One row per (userId, name). KV store for aggregated user-level features
+// computed from tip_views/tip_feedback/tip_scores. Numeric values land in
+// `value`; categorical/string values use `value_text` (never both). Entries
+// are recomputed lazily by the profile builder when older than `ttl_sec`.
+export const userProfileFeatures = sqliteTable('user_profile_features', {
+  userId: text('user_id').notNull().references(() => users.id),
+  name: text('name').notNull(),                       // e.g. 'completion_rate_30d'
+  value: integer('value', { mode: 'number' }),        // numeric (REAL stored as number); null if categorical
+  valueText: text('value_text'),                       // categorical/string; null if numeric
+  updatedAt: text('updated_at').notNull(),
+  ttlSec: integer('ttl_sec').notNull(),                // staleness threshold; 0 = never auto-refresh
+});
+
 // ── Simulation runs ──────────────────────────────────────────────────────────
 // One row per offline simulation run (two-policy comparison).
 export const simRuns = sqliteTable('sim_runs', {
diff --git a/services/api/src/profile/__tests__/builder.test.ts b/services/api/src/profile/__tests__/builder.test.ts
new file mode 100644
index 0000000..8403f2b
--- /dev/null
+++ b/services/api/src/profile/__tests__/builder.test.ts
@@ -0,0 +1,159 @@
+/**
+ * Profile builder tests — exercise lazy refresh, TTL skip, and rebuild.
+ * Uses an in-memory SQLite with the profile + tip tables; mocks db/index.js
+ * so getProfile/rebuildProfile see the test DB.
+ */
+import { describe, it, expect, vi, beforeAll, beforeEach } from 'vitest';
+import { makeTestDb } from '../../test/db.js';
+import {
+  users,
+  tipViews,
+  tipFeedback,
+  userProfileFeatures,
+} from '../../db/schema.js';
+import { eq } from 'drizzle-orm';
+
+const testDb = makeTestDb();
+vi.mock('../../db/index.js', () => ({ db: testDb, rawSqlite: testDb.rawSqlite }));
+
+const { getProfile, rebuildProfile, readProfile } = await import('../builder.js');
+
+const NOW = new Date().toISOString();
+// 30s ago — magic-zone dwell when paired with a 'done'
+const SHORT_AGO = new Date(Date.now() - 30_000).toISOString();
+
+beforeAll(async () => {
+  await testDb.insert(users).values([
+    { id: 'pf-user-1', email: 'pf1@test.com', role: 'user', consentGiven: true, consentAt: NOW, createdAt: NOW },
+    { id: 'pf-user-empty', email: 'pfempty@test.com', role: 'user', consentGiven: true, consentAt: NOW, createdAt: NOW },
+  ]);
+});
+
+beforeEach(async () => {
+  // Re-seed tip data each test so mutations in one test don't leak into the next.
+  // pf-user-1: 4 tips served, 2 done, 1 dismiss, 1 no reaction.
+  await testDb.delete(userProfileFeatures);
+  await testDb.delete(tipFeedback);
+  await testDb.delete(tipViews);
+  await testDb.insert(tipViews).values([
+    { id: 'pv-1', userId: 'pf-user-1', tipId: 'tip:1', servedAt: SHORT_AGO },
+    { id: 'pv-2', userId: 'pf-user-1', tipId: 'tip:2', servedAt: SHORT_AGO },
+    { id: 'pv-3', userId: 'pf-user-1', tipId: 'tip:3', servedAt: SHORT_AGO },
+    { id: 'pv-4', userId: 'pf-user-1', tipId: 'tip:4', servedAt: SHORT_AGO },
+  ]);
+  await testDb.insert(tipFeedback).values([
+    { id: 'pf-1', userId: 'pf-user-1', tipId: 'tip:1', action: 'done',    dwellMs: 30_000, rewardMilli: 1000,  createdAt: NOW },
+    { id: 'pf-2', userId: 'pf-user-1', tipId: 'tip:2', action: 'done',    dwellMs: 60_000, rewardMilli: 1000,  createdAt: NOW },
+    { id: 'pf-3', userId: 'pf-user-1', tipId: 'tip:3', action: 'dismiss', dwellMs: 10_000, rewardMilli: -1000, createdAt: NOW },
+  ]);
+});
+
+describe('getProfile — first call computes + stores all features', () => {
+  it('returns numeric values matching the seeded data', async () => {
+    const profile = await getProfile('pf-user-1');
+    // 2 done out of 4 served = 0.5
+    expect(profile.completion_rate_30d).toBeCloseTo(0.5, 5);
+    // 1 dismiss out of 4 = 0.25
+    expect(profile.dismiss_rate_30d).toBeCloseTo(0.25, 5);
+    // mean dwell over 3 reacted: (30 + 60 + 10) / 3 = 33.33s
+    expect(profile.mean_dwell_ms_30d).toBeCloseTo(33_333.33, 0);
+    // tip volume served = 4
+    expect(profile.tip_volume_30d).toBe(4);
+    // preferred_hour = hour of NOW (only 'done' reactions seeded)
+    expect(typeof profile.preferred_hour).toBe('number');
+  });
+
+  it('persists rows with updated_at + ttl_sec', async () => {
+    await getProfile('pf-user-1');
+    const rows = await testDb
+      .select()
+      .from(userProfileFeatures)
+      .where(eq(userProfileFeatures.userId, 'pf-user-1'));
+    // 5 features in the registry → 5 rows
+    expect(rows).toHaveLength(5);
+    for (const row of rows) {
+      expect(row.updatedAt).toBeTruthy();
+      expect(row.ttlSec).toBeGreaterThan(0);
+    }
+  });
+});
+
+describe('getProfile — fresh row is returned without recompute', () => {
+  it('does not change updated_at on the second call within TTL', async () => {
+    await getProfile('pf-user-1');
+    const before = await testDb
+      .select()
+      .from(userProfileFeatures)
+      .where(eq(userProfileFeatures.userId, 'pf-user-1'));
+    const beforeTimestamps = before.map((r) => `${r.name}:${r.updatedAt}`).sort();
+
+    // Bend reality: change underlying tip data after the first compute.
+    // If the cache is honored, the returned value should NOT reflect this change.
+    await testDb.delete(tipFeedback);
+
+    const profile = await getProfile('pf-user-1');
+    const after = await testDb
+      .select()
+      .from(userProfileFeatures)
+      .where(eq(userProfileFeatures.userId, 'pf-user-1'));
+    const afterTimestamps = after.map((r) => `${r.name}:${r.updatedAt}`).sort();
+
+    expect(afterTimestamps).toEqual(beforeTimestamps);
+    // Cached completion_rate_30d should still be 0.5, not 0
+    expect(profile.completion_rate_30d).toBeCloseTo(0.5, 5);
+  });
+});
+
+describe('getProfile — stale row triggers recompute', () => {
+  it('refreshes when updated_at is older than ttl_sec', async () => {
+    // Pre-seed a stale row for completion_rate_30d (1 hour old, ttl = 6h is the registry default).
+    // To make it stale we need an updated_at older than ttl_sec — pick way-back.
+    const yearAgo = new Date(Date.now() - 365 * 86_400_000).toISOString();
+    await testDb.insert(userProfileFeatures).values({
+      userId: 'pf-user-1',
+      name: 'completion_rate_30d',
+      value: 0.99,             // nonsense value to prove a refresh happened
+      valueText: null,
+      updatedAt: yearAgo,
+      ttlSec: 6 * 3600,
+    });
+
+    const profile = await getProfile('pf-user-1');
+    expect(profile.completion_rate_30d).toBeCloseTo(0.5, 5);  // recomputed, not cached
+  });
+});
+
+describe('rebuildProfile + readProfile', () => {
+  it('rebuildProfile recomputes everything regardless of TTL', async () => {
+    await rebuildProfile('pf-user-1');
+    // Wipe reactions; views remain. SUM(done)/COUNT(*) = 0/4 = 0, not null.
+    await testDb.delete(tipFeedback);
+    const refreshed = await rebuildProfile('pf-user-1');
+    expect(refreshed.completion_rate_30d).toBe(0);
+    expect(refreshed.dismiss_rate_30d).toBe(0);
+  });
+
+  it('readProfile returns whatever is stored without computing', async () => {
+    expect(readProfile('pf-user-1')).toEqual({});
+    await getProfile('pf-user-1');
+    const stored = readProfile('pf-user-1');
+    expect(Object.keys(stored).sort()).toEqual([
+      'completion_rate_30d',
+      'dismiss_rate_30d',
+      'mean_dwell_ms_30d',
+      'preferred_hour',
+      'tip_volume_30d',
+    ]);
+  });
+});
+
+describe('getProfile — empty user', () => {
+  it('returns nulls / zeros without throwing', async () => {
+    const profile = await getProfile('pf-user-empty');
+    expect(profile.completion_rate_30d).toBeNull();  // 0/0 → NULLIF guard
+    expect(profile.dismiss_rate_30d).toBeNull();
+    expect(profile.mean_dwell_ms_30d).toBeNull();
+    expect(profile.preferred_hour).toBeNull();
+    expect(profile.tip_volume_30d).toBe(0);
+  });
+});
diff --git a/services/api/src/profile/builder.ts b/services/api/src/profile/builder.ts
new file mode 100644
index 0000000..a1aa858
--- /dev/null
+++ b/services/api/src/profile/builder.ts
@@ -0,0 +1,107 @@
+/**
+ * User-profile builder (#81 phase A).
+ *
+ * Lazy refresh: `getProfile(userId)` returns every registered feature as a
+ * dict, recomputing any entry whose stored row is older than its `ttlSec`
+ * (or doesn't exist yet). All compute calls go against the raw better-sqlite3
+ * client because the SQL aggregations live in the registry.
+ *
+ * Phase B will add an event subscription so reactions update the relevant
+ * features incrementally instead of waiting for the next TTL window.
+ */
+import type Database from 'better-sqlite3';
+import { db, rawSqlite } from '../db/index.js';
+import { userProfileFeatures } from '../db/schema.js';
+import { and, eq } from 'drizzle-orm';
+import { FEATURES, type FeatureDefinition, type FeatureValue } from './registry.js';
+
+export type Profile = Record<string, number | string | null>;
+
+interface StoredRow {
+  name: string;
+  value: number | null;
+  value_text: string | null;
+  updated_at: string;
+  ttl_sec: number;
+}
+
+function readStored(userId: string): Map<string, StoredRow> {
+  const rows = rawSqlite
+    .prepare(`SELECT name, value, value_text, updated_at, ttl_sec FROM user_profile_features WHERE user_id = ?`)
+    .all(userId) as StoredRow[];
+  return new Map(rows.map((r) => [r.name, r]));
+}
+
+function isFresh(row: StoredRow, now: number): boolean {
+  if (row.ttl_sec === 0) return true;
+  const ageSec = (now - new Date(row.updated_at).getTime()) / 1000;
+  return ageSec < row.ttl_sec;
+}
+
+function valueOf(row: StoredRow): number | string | null {
+  return row.value ?? row.value_text;
+}
+
+async function upsertFeature(
+  userId: string,
+  feature: FeatureDefinition,
+  result: FeatureValue,
+  updatedAt: string,
+): Promise<void> {
+  const value = result.kind === 'numeric' ? result.value : null;
+  const valueText = result.kind === 'categorical' ? result.value : null;
+  await db
+    .insert(userProfileFeatures)
+    .values({
+      userId,
+      name: feature.name,
+      value,
+      valueText,
+      updatedAt,
+      ttlSec: feature.ttlSec,
+    })
+    .onConflictDoUpdate({
+      target: [userProfileFeatures.userId, userProfileFeatures.name],
+      set: { value, valueText, updatedAt, ttlSec: feature.ttlSec },
+    });
+}
+
+/** Lazily refresh + return the full profile as `{ feature_name: value }`. */
+export async function getProfile(userId: string, sqlite: Database.Database = rawSqlite): Promise<Profile> {
+  const stored = readStored(userId);
+  const now = Date.now();
+  const nowIso = new Date(now).toISOString();
+  const out: Profile = {};
+
+  for (const feature of FEATURES) {
+    const row = stored.get(feature.name);
+    if (row && isFresh(row, now)) {
+      out[feature.name] = valueOf(row);
+      continue;
+    }
+    const result = feature.compute(userId, sqlite);
+    await upsertFeature(userId, feature, result, nowIso);
+    out[feature.name] = result.value;
+  }
+  return out;
+}
+
+/** Force-recompute every feature. Useful for tests + future admin "rebuild" button. */
+export async function rebuildProfile(userId: string, sqlite: Database.Database = rawSqlite): Promise<Profile> {
+  const nowIso = new Date().toISOString();
+  const out: Profile = {};
+  for (const feature of FEATURES) {
+    const result = feature.compute(userId, sqlite);
+    await upsertFeature(userId, feature, result, nowIso);
+    out[feature.name] = result.value;
+  }
+  return out;
+}
+
+/** Read-only fetch — no compute, no upsert. Returns whatever is stored (possibly stale, possibly empty). */
+export function readProfile(userId: string): Profile {
+  const stored = readStored(userId);
+  const out: Profile = {};
+  for (const [name, row] of stored) out[name] = valueOf(row);
+  return out;
+}
diff --git a/services/api/src/profile/registry.ts b/services/api/src/profile/registry.ts
new file mode 100644
index 0000000..f38e01d
--- /dev/null
+++ b/services/api/src/profile/registry.ts
@@ -0,0 +1,133 @@
+/**
+ * User-profile feature registry (#81 phase A).
+ *
+ * Each entry declares a feature that can be aggregated from existing tables
+ * (tip_views, tip_feedback, tip_scores) and stored in user_profile_features.
+ * The Python schema mirror in `ml/features/profile_schema.py` documents the
+ * same contract so ml/serving knows what fields to expect.
+ *
+ * Compute functions take the raw better-sqlite3 client (rather than drizzle)
+ * because every feature here is a single SQL aggregation — query builder
+ * overhead and type yoga aren't worth it for one-line SELECTs.
+ */
+import type Database from 'better-sqlite3';
+
+export type FeatureValue =
+  | { kind: 'numeric'; value: number | null }
+  | { kind: 'categorical'; value: string | null };
+
+export interface FeatureDefinition {
+  name: string;
+  dtype: 'numeric' | 'categorical';
+  /** Seconds before the stored value is considered stale and recomputed. */
+  ttlSec: number;
+  /** Human-readable purpose; surfaced in admin UI eventually. */
+  description: string;
+  /** Compute the feature for one user against the live DB. */
+  compute(userId: string, db: Database.Database): FeatureValue;
+}
+
+const HOUR = 3600;
+const DAY = 86_400;
+
+// 30-day window pinned to "now" each compute. Using `datetime('now','-30 days')`
+// keeps the SQL portable between the prod DB and in-memory test DBs.
+const SINCE_30D = `datetime('now', '-30 days')`;
+
+export const FEATURES: readonly FeatureDefinition[] = [
+  {
+    name: 'completion_rate_30d',
+    dtype: 'numeric',
+    ttlSec: 6 * HOUR,
+    description: 'Fraction of tips served in the last 30 days that received a "done" reaction.',
+    compute(userId, db) {
+      const row = db
+        .prepare(`
+          SELECT
+            CAST(SUM(CASE WHEN tf.action = 'done' THEN 1 ELSE 0 END) AS REAL)
+              / NULLIF(COUNT(*), 0) AS rate
+          FROM tip_views tv
+          LEFT JOIN tip_feedback tf ON tf.tip_id = tv.tip_id
+          WHERE tv.user_id = ? AND tv.served_at >= ${SINCE_30D}
+        `)
+        .get(userId) as { rate: number | null } | undefined;
+      return { kind: 'numeric', value: row?.rate ?? null };
+    },
+  },
+  {
+    name: 'dismiss_rate_30d',
+    dtype: 'numeric',
+    ttlSec: 6 * HOUR,
+    description: 'Fraction of tips served in the last 30 days that received a "dismiss" reaction.',
+    compute(userId, db) {
+      const row = db
+        .prepare(`
+          SELECT
+            CAST(SUM(CASE WHEN tf.action = 'dismiss' THEN 1 ELSE 0 END) AS REAL)
+              / NULLIF(COUNT(*), 0) AS rate
+          FROM tip_views tv
+          LEFT JOIN tip_feedback tf ON tf.tip_id = tv.tip_id
+          WHERE tv.user_id = ? AND tv.served_at >= ${SINCE_30D}
+        `)
+        .get(userId) as { rate: number | null } | undefined;
+      return { kind: 'numeric', value: row?.rate ?? null };
+    },
+  },
+  {
+    name: 'mean_dwell_ms_30d',
+    dtype: 'numeric',
+    ttlSec: 6 * HOUR,
+    description: 'Average dwell time (ms between served and reacted) over the last 30 days.',
+    compute(userId, db) {
+      const row = db
+        .prepare(`
+          SELECT AVG(tf.dwell_ms) AS avg_ms
+          FROM tip_feedback tf
+          WHERE tf.user_id = ? AND tf.created_at >= ${SINCE_30D} AND tf.dwell_ms IS NOT NULL
+        `)
+        .get(userId) as { avg_ms: number | null } | undefined;
+      return { kind: 'numeric', value: row?.avg_ms ?? null };
+    },
+  },
+  {
+    name: 'preferred_hour',
+    dtype: 'numeric',
+    ttlSec: DAY,
+    description: 'Hour-of-day with the most "done" reactions in the last 30 days (0–23).',
+    compute(userId, db) {
+      const row = db
+        .prepare(`
+          SELECT CAST(strftime('%H', tf.created_at) AS INTEGER) AS hour, COUNT(*) AS n
+          FROM tip_feedback tf
+          WHERE tf.user_id = ?
+            AND tf.action = 'done'
+            AND tf.created_at >= ${SINCE_30D}
+          GROUP BY hour
+          ORDER BY n DESC
+          LIMIT 1
+        `)
+        .get(userId) as { hour: number; n: number } | undefined;
+      return { kind: 'numeric', value: row?.hour ?? null };
+    },
+  },
+  {
+    name: 'tip_volume_30d',
+    dtype: 'numeric',
+    ttlSec: HOUR,
+    description: 'Number of tips served to the user in the last 30 days.',
+    compute(userId, db) {
+      const row = db
+        .prepare(`
+          SELECT COUNT(*) AS n
+          FROM tip_views
+          WHERE user_id = ? AND served_at >= ${SINCE_30D}
+        `)
+        .get(userId) as { n: number } | undefined;
+      return { kind: 'numeric', value: row?.n ?? 0 };
+    },
+  },
+] as const;
+
+export function findFeature(name: string): FeatureDefinition | undefined {
+  return FEATURES.find((f) => f.name === name);
+}
diff --git a/services/api/src/routes/__tests__/recommender.test.ts b/services/api/src/routes/__tests__/recommender.test.ts
index 3882d89..f68475c 100644
--- a/services/api/src/routes/__tests__/recommender.test.ts
+++ b/services/api/src/routes/__tests__/recommender.test.ts
@@ -13,7 +13,7 @@ import { users, integrationTokens, tipScores } from '../../db/schema.js';
 
 const testDb = makeTestDb();
 
-vi.mock('../../db/index.js', () => ({ db: testDb }));
+vi.mock('../../db/index.js', () => ({ db: testDb, rawSqlite: testDb.rawSqlite }));
 vi.mock('../../middleware/session.js', () => ({
   sessionMiddleware: (_req: express.Request, _res: express.Response, next: express.NextFunction) => next(),
   requireAuth: (req: express.Request, _res: express.Response, next: express.NextFunction) => {
diff --git a/services/api/src/routes/recommender.ts b/services/api/src/routes/recommender.ts
index 1f5ee57..40dbac5 100644
--- a/services/api/src/routes/recommender.ts
+++ b/services/api/src/routes/recommender.ts
@@ -10,6 +10,7 @@ import type { TipCandidate, Signal } from '@oo/shared-types';
 import { todoistSource, dueAgeDays } from '../signals/todoist.js';
 export { dueAgeDays };
 import { SignalAggregator } from '../signals/aggregator.js';
+import { getProfile, type Profile } from '../profile/builder.js';
 
 const router: ExpressRouter = Router();
 
@@ -82,6 +83,7 @@ function signalToCandidate(signal: Signal): TipCandidate {
 async function remotePolicy(
   userId: string,
   tasks: TipCandidate[],
+  profile: Profile,
 ): Promise<{ tipId: string; score: number; policy: string } | null> {
   const hour = new Date().getHours();
   const dayOfWeek = new Date().getDay();
@@ -96,6 +98,7 @@ async function remotePolicy(
       features: t.features,
     })),
     context: { hour_of_day: hour, day_of_week: dayOfWeek },
+    profile_features: profile,
   };
 
   // Active policy: egreedy-v1 (selected over linucb-v1 after offline sim — ADR-0007)
@@ -141,6 +144,7 @@ async function fetchLlmCandidates(
   hour: number,
   dayOfWeek: number,
   promptVersion: string | null,
+  profile: Profile,
 ): Promise<LlmGenerateResult> {
   try {
     const tasks = signals.slice(0, 10).map((s) => ({
@@ -156,6 +160,7 @@ async function fetchLlmCandidates(
         user_id: userId,
         context: { tasks, hour_of_day: hour, day_of_week: dayOfWeek },
         n: 3,
+        profile_features: profile,
         ...(promptVersion ? { prompt_version: promptVersion } : {}),
       }),
       signal: AbortSignal.timeout(15_000),
@@ -208,6 +213,8 @@ router.post('/recommend', requireAuth, async (req: AuthenticatedRequest, res: Re
 
   // Stage 1: assemble candidates — aggregated signals + LLM-generated advice (parallel)
   const signals = await aggregator.fetchAll(req.userId!);
+  // Refresh + load the user-level profile feature dict (lazy TTL refresh).
+  const profile = await getProfile(req.userId!);
 
   const signalCandidates = signals.map(signalToCandidate);
   const requestedPromptVersion = pickPromptVersion();
@@ -217,6 +224,7 @@ router.post('/recommend', requireAuth, async (req: AuthenticatedRequest, res: Re
     hour,
     dayOfWeek,
     requestedPromptVersion,
+    profile,
   );
 
   const allCandidates: TipCandidate[] = [...signalCandidates, ...llmResult.candidates];
@@ -231,7 +239,7 @@ router.post('/recommend', requireAuth, async (req: AuthenticatedRequest, res: Re
   const t0 = Date.now();
 
   // Stage 2: score — egreedy bandit with random fallback
-  const scored = await remotePolicy(req.userId!, allCandidates);
+  const scored = await remotePolicy(req.userId!, allCandidates, profile);
   const latencyMs = Date.now() - t0;
   const tip = scored
     ? (allCandidates.find((t) => t.id === scored.tipId) ?? randomPolicy(allCandidates))
diff --git a/services/api/src/test/db.ts b/services/api/src/test/db.ts
index b16af86..ca4aceb 100644
--- a/services/api/src/test/db.ts
+++ b/services/api/src/test/db.ts
@@ -105,6 +105,16 @@ export function makeTestDb(): DrizzleDb & { rawSqlite: BetterSqlite3Database } {
       created_at TEXT NOT NULL
     );
 
+    CREATE TABLE IF NOT EXISTS user_profile_features (
+      user_id TEXT NOT NULL REFERENCES users(id),
+      name TEXT NOT NULL,
+      value REAL,
+      value_text TEXT,
+      updated_at TEXT NOT NULL,
+      ttl_sec INTEGER NOT NULL,
+      PRIMARY KEY (user_id, name)
+    );
+
     CREATE TABLE IF NOT EXISTS sim_runs (
       id TEXT PRIMARY KEY,
       policy_a TEXT NOT NULL,