fix(edge): meter and size-cap knowledge embeddings in embed-chunks and search-knowledge

server/supabase/functions/_shared/embedding-quota.fake.ts

@@ -0,0 +1,25 @@
+// Test double for EmbeddingUsageStore (not a test file itself).
+import { EMBEDDING_QUOTA_FEATURE, type EmbeddingUsageStore } from './embedding-quota.ts'
+import type { PlanQuotaTier } from './core-contract.generated.ts'
+
+/** In-memory daily_usage keyed by date; `today` is the date increments land on. */
+export class MemoryUsageStore implements EmbeddingUsageStore {
+  rows = new Map<string, number>()
+  failIncrement = false
+  constructor(public tier: PlanQuotaTier, public today: string) {}
+  readTier(): Promise<PlanQuotaTier> {
+    return Promise.resolve(this.tier)
+  }
+  increment(_userId: string, feature: string, amount: number): Promise<number> {
+    if (this.failIncrement) return Promise.reject(new Error('down'))
+    if (feature !== EMBEDDING_QUOTA_FEATURE) return Promise.reject(new Error(`unexpected feature ${feature}`))
+    const next = (this.rows.get(this.today) ?? 0) + amount
+    this.rows.set(this.today, next)
+    return Promise.resolve(next)
+  }
+  sumBetween(_userId: string, _feature: string, fromDate: string, beforeDate: string): Promise<number> {
+    let sum = 0
+    for (const [date, count] of this.rows) if (date >= fromDate && date < beforeDate) sum += count
+    return Promise.resolve(sum)
+  }
+}

server/supabase/functions/_shared/embedding-quota.test.ts

@@ -0,0 +1,85 @@
+import {
+  EMBEDDING_LIMITS,
+  EMBEDDING_QUOTA,
+  embeddingUnits,
+  firstOversizedChunk,
+  planEmbeddingBatches,
+  refundEmbeddingUnits,
+  reserveEmbeddingUnits,
+  usageWindowStart,
+} from './embedding-quota.ts'
+import { MemoryUsageStore } from './embedding-quota.fake.ts'
+
+function assert(condition: boolean, message: string): asserts condition {
+  if (!condition) throw new Error(message)
+}
+
+const NOW = new Date('2026-09-28T12:00:00Z')
+
+Deno.test('units count every started 1,000 characters, at least one per input', () => {
+  assert(embeddingUnits(['a']) === 1, 'short input')
+  assert(embeddingUnits(['x'.repeat(1_000), 'x'.repeat(1_001)]) === 3, 'boundary rounding')
+})
+
+Deno.test('oversized chunks are found before any spend', () => {
+  const ok = { content: 'x'.repeat(EMBEDDING_LIMITS.maxChunkChars) }
+  const big = { content: 'x'.repeat(EMBEDDING_LIMITS.maxChunkChars + 1) }
+  assert(firstOversizedChunk([ok, ok]) === -1, 'at-limit chunk rejected')
+  assert(firstOversizedChunk([ok, big]) === 1, 'oversized chunk missed')
+})
+
+Deno.test('batches stay under the input and character caps', () => {
+  const small = Array.from({ length: 250 }, (_, i) => ({ content: `c${i}` }))
+  assert(planEmbeddingBatches(small).map((b) => b.length).join(',') === '100,100,50', 'input cap')
+  const large = Array.from({ length: 30 }, () => ({ content: 'x'.repeat(8_000) }))
+  const batches = planEmbeddingBatches(large)
+  assert(batches.every((b) => b.reduce((s, c) => s + c.content.length, 0) <= EMBEDDING_LIMITS.maxBatchChars), 'char cap')
+  assert(batches.flat().length === 30, 'chunks lost')
+})
+
+Deno.test('weekly window covers the six days before today', () => {
+  assert(usageWindowStart('weekly', NOW) === '2026-09-22', 'weekly start')
+  assert(usageWindowStart('daily', NOW) === null, 'daily has no earlier window')
+})
+
+Deno.test('free tier is capped weekly and a denied reservation is rolled back', async () => {
+  const store = new MemoryUsageStore('free', '2026-09-28')
+  store.rows.set('2026-09-25', EMBEDDING_QUOTA.free.limit - 10)
+  const denied = await reserveEmbeddingUnits(store, 'u1', 11, NOW)
+  assert(!denied.allowed, 'over-limit reservation was allowed')
+  assert((store.rows.get('2026-09-28') ?? 0) === 0, 'denied units were kept')
+  const allowed = await reserveEmbeddingUnits(store, 'u1', 10, NOW)
+  assert(allowed.allowed && allowed.current === EMBEDDING_QUOTA.free.limit, 'exact fit denied')
+})
+
+Deno.test('usage older than the window does not count', async () => {
+  const store = new MemoryUsageStore('free', '2026-09-28')
+  store.rows.set('2026-09-21', EMBEDDING_QUOTA.free.limit)
+  assert((await reserveEmbeddingUnits(store, 'u1', 5, NOW)).allowed, 'stale usage counted')
+})
+
+Deno.test('enterprise is unlimited but still counted', async () => {
+  const store = new MemoryUsageStore('enterprise', '2026-09-28')
+  const result = await reserveEmbeddingUnits(store, 'u1', 1_000_000, NOW)
+  assert(result.allowed && store.rows.get('2026-09-28') === 1_000_000, 'unlimited tier not counted')
+})
+
+Deno.test('refunds are capped by the reservation and skipped after the day rolls over', async () => {
+  const store = new MemoryUsageStore('pro', '2026-09-28')
+  const reservation = await reserveEmbeddingUnits(store, 'u1', 40, NOW)
+  await refundEmbeddingUnits(store, 'u1', reservation, 1_000, NOW)
+  assert(store.rows.get('2026-09-28') === 0, 'refund exceeded the reserved units')
+
+  const again = await reserveEmbeddingUnits(store, 'u1', 40, NOW)
+  store.today = '2026-09-29'
+  await refundEmbeddingUnits(store, 'u1', again, 40, new Date('2026-09-29T00:00:01Z'))
+  assert(!store.rows.has('2026-09-29'), 'next-day refund credited the new day')
+})
+
+Deno.test('a store failure during refund is swallowed', async () => {
+  const store = new MemoryUsageStore('pro', '2026-09-28')
+  const reservation = await reserveEmbeddingUnits(store, 'u1', 3, NOW)
+  store.failIncrement = true
+  await refundEmbeddingUnits(store, 'u1', reservation, 3, NOW)
+  assert(store.rows.get('2026-09-28') === 3, 'usage changed')
+})

server/supabase/functions/_shared/embedding-quota.ts

@@ -0,0 +1,250 @@
+// server/supabase/functions/_shared/embedding-quota.ts
+// Cost guard for the paid OpenAI embedding calls made by embed-chunks and
+// search-knowledge.
+//
+// Before this module both functions only checked the JWT: any signed-in account
+// could insert an unbounded number of knowledge_chunks rows (RLS only checks
+// document ownership, `content` is unbounded text) and have every one of them
+// embedded, repeatedly, and search-knowledge embedded a 4,000-char query per
+// call with no counter. stt/llm/realtime all go through quota.ts; embeddings
+// did not.
+//
+// Policy (pure):   size caps + per-tier unit budget + batch planning.
+// Port:            EmbeddingUsageStore (tier lookup + atomic counter).
+// Adapter:         createSupabaseEmbeddingUsageStore (subscriptions + daily_usage
+//                  via the existing service-role `increment_daily_usage` RPC).
+//
+// TODO(plan-catalog): the per-tier budget below belongs in
+// packages/core/src/plan-catalog.ts `PLAN_QUOTA` (feature `knowledge_embedding`)
+// and should be read from core-contract.generated.ts once it is added there.
+
+import type { createClient } from '@supabase/supabase-js'
+import type { PlanQuotaPeriod, PlanQuotaTier } from './core-contract.generated.ts'
+
+/** daily_usage.feature key for embedding spend. */
+export const EMBEDDING_QUOTA_FEATURE = 'knowledge_embedding'
+
+export const EMBEDDING_LIMITS = Object.freeze({
+  /** Longest chunk accepted for embedding (the OpenAI per-input cap is ~8k tokens). */
+  maxChunkChars: 8_000,
+  /** Most chunks one document may have. Desktop chunking stops at 2,000 chunks. */
+  maxChunksPerDocument: 2_000,
+  /** Longest search query accepted. */
+  maxQueryChars: 4_000,
+  /** Inputs per provider request. */
+  maxBatchInputs: 100,
+  /** Characters per provider request (keeps a batch under the per-request token cap). */
+  maxBatchChars: 100_000,
+  /** One quota unit = up to this many characters of embedded text. */
+  charsPerUnit: 1_000,
+})
+
+export interface EmbeddingQuotaPolicy {
+  /** Units per period. -1 = unlimited, 0 = not available. */
+  limit: number
+  period: PlanQuotaPeriod
+}
+
+/**
+ * Units (1 unit = up to 1,000 chars) per tier. Cloud knowledge is offered on
+ * every tier (web/mobile have no paywall for it), so free gets a small weekly
+ * budget instead of none: 5,000 units ≈ 5M chars ≈ 20 maximum-size mobile
+ * documents a week.
+ */
+export const EMBEDDING_QUOTA: Readonly<Record<PlanQuotaTier, EmbeddingQuotaPolicy>> = Object.freeze({
+  free: { limit: 5_000, period: 'weekly' },
+  pro: { limit: 50_000, period: 'daily' },
+  pro_plus: { limit: 150_000, period: 'daily' },
+  team: { limit: 300_000, period: 'daily' },
+  enterprise: { limit: -1, period: 'daily' },
+})
+
+const QUOTA_TIERS: readonly PlanQuotaTier[] = ['free', 'pro', 'pro_plus', 'team', 'enterprise']
+
+export function normalizeQuotaTier(value: unknown): PlanQuotaTier {
+  return typeof value === 'string' && (QUOTA_TIERS as readonly string[]).includes(value)
+    ? value as PlanQuotaTier
+    : 'free'
+}
+
+export function embeddingPolicyFor(tier: PlanQuotaTier): EmbeddingQuotaPolicy {
+  return EMBEDDING_QUOTA[tier] ?? { limit: 0, period: 'daily' }
+}
+
+/** Units one text costs: every started 1,000 characters, at least 1. */
+export function embeddingUnitsFor(text: string): number {
+  return Math.max(1, Math.ceil(text.length / EMBEDDING_LIMITS.charsPerUnit))
+}
+
+export function embeddingUnits(texts: readonly string[]): number {
+  return texts.reduce((sum, text) => sum + embeddingUnitsFor(text), 0)
+}
+
+/** Index of the first chunk over `maxChunkChars`, or -1. */
+export function firstOversizedChunk(chunks: readonly { content: string }[]): number {
+  return chunks.findIndex((chunk) => chunk.content.length > EMBEDDING_LIMITS.maxChunkChars)
+}
+
+/** Split chunks into provider requests bounded by input count and characters. */
+export function planEmbeddingBatches<T extends { content: string }>(chunks: readonly T[]): T[][] {
+  const batches: T[][] = []
+  let current: T[] = []
+  let chars = 0
+  for (const chunk of chunks) {
+    const size = chunk.content.length
+    if (
+      current.length > 0
+      && (current.length >= EMBEDDING_LIMITS.maxBatchInputs || chars + size > EMBEDDING_LIMITS.maxBatchChars)
+    ) {
+      batches.push(current)
+      current = []
+      chars = 0
+    }
+    current.push(chunk)
+    chars += size
+  }
+  if (current.length > 0) batches.push(current)
+  return batches
+}
+
+function isoDate(date: Date): string {
+  return date.toISOString().slice(0, 10)
+}
+
+/** First date (inclusive) of the usage window before today, or null for a daily period. */
+export function usageWindowStart(period: PlanQuotaPeriod, now: Date): string | null {
+  if (period !== 'weekly') return null
+  const start = new Date(now.getTime())
+  start.setUTCDate(start.getUTCDate() - 6)
+  return isoDate(start)
+}
+
+// ── Port ────────────────────────────────────────────────────────────────
+
+export interface EmbeddingUsageStore {
+  readTier(userId: string): Promise<PlanQuotaTier>
+  /** Atomically add `amount` (may be negative) to today's counter; returns the new count. */
+  increment(userId: string, feature: string, amount: number): Promise<number>
+  /** Sum of counters with fromDate <= date < beforeDate. */
+  sumBetween(userId: string, feature: string, fromDate: string, beforeDate: string): Promise<number>
+}
+
+export interface EmbeddingReservation {
+  allowed: boolean
+  /** Units held by this reservation (0 when denied or nothing was requested). */
+  units: number
+  /** Usage in the current window including this reservation when allowed. */
+  current: number
+  limit: number
+  period: PlanQuotaPeriod
+  tier: PlanQuotaTier
+  /** UTC date the units were counted on. */
+  date: string
+}
+
+/**
+ * Reserve `units` before spending. The counter is incremented first (atomic in
+ * the database) and rolled back when the window total then exceeds the limit,
+ * so concurrent requests can never admit more than the limit between them.
+ * Throws when the store fails: callers must fail closed.
+ */
+export async function reserveEmbeddingUnits(
+  store: EmbeddingUsageStore,
+  userId: string,
+  units: number,
+  now: Date = new Date(),
+): Promise<EmbeddingReservation> {
+  const tier = await store.readTier(userId)
+  const policy = embeddingPolicyFor(tier)
+  const date = isoDate(now)
+  const base = { limit: policy.limit, period: policy.period, tier, date }
+
+  if (units <= 0) return { ...base, allowed: true, units: 0, current: 0 }
+  if (policy.limit === 0) return { ...base, allowed: false, units: 0, current: 0 }
+
+  const today = await store.increment(userId, EMBEDDING_QUOTA_FEATURE, units)
+  if (policy.limit === -1) return { ...base, allowed: true, units, current: today }
+
+  const windowStart = usageWindowStart(policy.period, now)
+  const earlier = windowStart
+    ? await store.sumBetween(userId, EMBEDDING_QUOTA_FEATURE, windowStart, date)
+    : 0
+  const used = earlier + today
+  if (used > policy.limit) {
+    await store.increment(userId, EMBEDDING_QUOTA_FEATURE, -units)
+    return { ...base, allowed: false, units: 0, current: used - units }
+  }
+  return { ...base, allowed: true, units, current: used }
+}
+
+/**
+ * Give back units that were reserved but not spent. Best effort: a failure
+ * leaves the user slightly over-counted, never under-counted. A refund after
+ * the UTC day rolled over is skipped so it cannot credit the new day.
+ */
+export async function refundEmbeddingUnits(
+  store: EmbeddingUsageStore,
+  userId: string,
+  reservation: EmbeddingReservation,
+  units: number,
+  now: Date = new Date(),
+): Promise<void> {
+  const amount = Math.min(units, reservation.units)
+  if (amount <= 0 || isoDate(now) !== reservation.date) return
+  try {
+    await store.increment(userId, EMBEDDING_QUOTA_FEATURE, -amount)
+  } catch {
+    // over-counting is the safe direction
+  }
+}
+
+export function quotaExceededBody(reservation: EmbeddingReservation, requested: number): Record<string, unknown> {
+  return {
+    error: 'quota_exceeded',
+    feature: EMBEDDING_QUOTA_FEATURE,
+    requested,
+    current: reservation.current,
+    limit: reservation.limit,
+    period: reservation.period,
+    tier: reservation.tier,
+  }
+}
+
+// ── Supabase adapter ────────────────────────────────────────────────────
+
+type SupabaseClient = ReturnType<typeof createClient>
+
+export function createSupabaseEmbeddingUsageStore(client: SupabaseClient): EmbeddingUsageStore {
+  return {
+    async readTier(userId) {
+      const { data, error } = await client
+        .from('subscriptions')
+        .select('tier')
+        .eq('user_id', userId)
+        .maybeSingle()
+      if (error) throw new Error('Failed to read subscription tier.')
+      return normalizeQuotaTier((data as { tier?: unknown } | null)?.tier)
+    },
+    async increment(userId, feature, amount) {
+      const { data, error } = await client.rpc('increment_daily_usage', {
+        p_user_id: userId,
+        p_feature: feature,
+        p_amount: amount,
+      })
+      if (error || typeof data !== 'number') throw new Error('Failed to update embedding usage.')
+      return data
+    },
+    async sumBetween(userId, feature, fromDate, beforeDate) {
+      const { data, error } = await client
+        .from('daily_usage')
+        .select('count')
+        .eq('user_id', userId)
+        .eq('feature', feature)
+        .gte('date', fromDate)
+        .lt('date', beforeDate)
+      if (error) throw new Error('Failed to read embedding usage.')
+      const rows = (data ?? []) as Array<{ count: number | null }>
+      return rows.reduce((sum, row) => sum + (row.count ?? 0), 0)
+    },
+  }
+}

server/supabase/functions/_shared/json-response.ts

@@ -0,0 +1,30 @@
+// server/supabase/functions/_shared/json-response.ts
+// JSON response + auth-error mapping shared by the knowledge functions.
+
+import { corsHeaders } from './cors.ts'
+import type { AuthError } from './auth.ts'
+
+export function jsonResponse(status: number, body: Record<string, unknown>): Response {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+  })
+}
+
+export function isAuthError(error: unknown): error is AuthError {
+  return Boolean(
+    error
+    && typeof error === 'object'
+    && 'status' in error
+    && (error.status === 401 || error.status === 403)
+    && 'message' in error
+    && typeof error.message === 'string',
+  )
+}
+
+/** Map a thrown value to a response: auth errors keep their status, anything else is a 500. */
+export function errorResponse(error: unknown): Response {
+  // Same shape as auth.ts authErrorResponse, without loading the Supabase client.
+  if (isAuthError(error)) return jsonResponse(error.status, { error: error.message })
+  return jsonResponse(500, { error: 'internal_error' })
+}

server/supabase/functions/_shared/openai-embeddings.ts

@@ -0,0 +1,61 @@
+// server/supabase/functions/_shared/openai-embeddings.ts
+// Embedding provider port + OpenAI adapter shared by embed-chunks and
+// search-knowledge. The functions depend on the `EmbeddingProvider` port only,
+// so the quota/size policy can be tested without the network.
+
+export const EMBEDDING_MODEL = 'text-embedding-3-small'
+export const EMBEDDING_DIMENSIONS = 1536
+export const EMBEDDING_PROVIDER_TIMEOUT_MS = 45_000
+const OPENAI_EMBEDDINGS_URL = 'https://api.openai.com/v1/embeddings'
+
+export interface EmbeddingItem {
+  embedding?: unknown
+  index?: unknown
+}
+
+export type EmbeddingOutcome =
+  | { ok: true; data: EmbeddingItem[] }
+  /** `upstream`: transport error or non-2xx status. `invalid`: 2xx with an unusable body. */
+  | { ok: false; reason: 'upstream' | 'invalid' }
+
+export interface EmbeddingProvider {
+  embed(input: string | readonly string[]): Promise<EmbeddingOutcome>
+}
+
+export function isEmbedding(value: unknown): value is number[] {
+  return Array.isArray(value)
+    && value.length === EMBEDDING_DIMENSIONS
+    && value.every((entry) => typeof entry === 'number' && Number.isFinite(entry))
+}
+
+export function createOpenAIEmbeddingProvider(
+  apiKey: string,
+  fetchImpl: typeof fetch = fetch,
+): EmbeddingProvider {
+  return {
+    async embed(input) {
+      let response: Response
+      try {
+        response = await fetchImpl(OPENAI_EMBEDDINGS_URL, {
+          method: 'POST',
+          headers: {
+            Authorization: `Bearer ${apiKey}`,
+            'Content-Type': 'application/json',
+          },
+          body: JSON.stringify({
+            model: EMBEDDING_MODEL,
+            input,
+            dimensions: EMBEDDING_DIMENSIONS,
+          }),
+          signal: AbortSignal.timeout(EMBEDDING_PROVIDER_TIMEOUT_MS),
+        })
+      } catch {
+        return { ok: false, reason: 'upstream' }
+      }
+      if (!response.ok) return { ok: false, reason: 'upstream' }
+      const payload = await response.json().catch(() => null) as { data?: unknown } | null
+      if (!payload || !Array.isArray(payload.data)) return { ok: false, reason: 'invalid' }
+      return { ok: true, data: payload.data as EmbeddingItem[] }
+    },
+  }
+}