Sync public snapshot from freebuff-private

Source: CodebuffAI/freebuff-private@4f4f9a6cd4e9c7aa793a32fcdc8438ced2a0f5a2

Author: github-actions[bot]

common/src/__tests__/freebuff-models.test.ts

@@ -62,6 +62,8 @@ import {
   isFreebuffPremiumModelId,
   isFreebuffSessionModelAllowedForAccessTier,
   isFreebuffSessionModelAvailable,
+  freebuffModelUnavailableWindow,
+  FREEBUFF_DEPLOYMENT_HOURS_LABEL,
   isFreebuffSessionModelId,
   isFreebuffTracedModelId,
   isFreebuffWebDeemphasizedModelId,
@@ -1823,3 +1825,45 @@ describe('Muse Spark rate-limit fallback', () => {
     expect(MUSE_SPARK_FALLBACK_AFTER_MS).toBe(10_000)
   })
 })
+
+describe('the unavailability window matches the reason for the closure', () => {
+  /**
+   * Both refusal sites gate on isFreebuffSessionModelAvailable, which covers
+   * `deployment_hours` AND `off_peak_only`, and both hardcoded the
+   * deployment-hours label. So V4 Flash -- closed 5pm-3am Pacific for DeepSeek's
+   * peak pricing -- told users it was "available 9am ET-5pm PT every day":
+   * a different window, for a different reason, in two timezones at once.
+   */
+  const peak = new Date('2026-08-25T08:00:00Z')
+
+  test('a peak-closed model is told when it comes BACK, not our staffing hours', () => {
+    const window = freebuffModelUnavailableWindow(
+      FREEBUFF_DEEPSEEK_V4_FLASH_MODEL_ID,
+      peak,
+    )
+    expect(window).toContain('again at')
+    // The bug: the staffing label has nothing to do with peak pricing.
+    expect(window).not.toBe(FREEBUFF_DEPLOYMENT_HOURS_LABEL)
+    expect(window).not.toContain('ET')
+  })
+
+  /**
+   * No model carries `deployment_hours` today -- the catalog is `always` and
+   * `off_peak_only` only -- so the staffing label is reachable from the
+   * LIMITED-OFFER branch and not from this one. The resolver still returns it
+   * as the default rather than inventing a window for a closure it does not
+   * recognise, which is why this asserts the DEFAULT rather than a model that
+   * would have to be invented to test it.
+   */
+  test('an unrecognised closure falls back to the staffing label, not a guess', () => {
+    expect(freebuffModelUnavailableWindow('mimo/mimo-v2.5', peak)).toBe(
+      FREEBUFF_DEPLOYMENT_HOURS_LABEL,
+    )
+  })
+
+  test('it reads as a sentence in the template that renders it', () => {
+    // freebuffSession.ts renders `${model} is available ${availableHours}.`
+    const s = `X is available ${freebuffModelUnavailableWindow(FREEBUFF_DEEPSEEK_V4_FLASH_MODEL_ID, peak)}.`
+    expect(s).toMatch(/^X is available again at .+\.$/)
+  })
+})

common/src/constants/freebuff-models.ts

@@ -6,6 +6,7 @@ import {
 } from '../util/zoned-time'
 import {
   deepSeekExpensiveWindowEndsAt,
+  formatDeepSeekExpensiveWindowReturn,
   isDeepSeekExpensiveWindow,
 } from './freebuff-peak-hours'
 import { mimoModels } from './model-config'
@@ -2920,6 +2921,27 @@ function isAvailableAt(
   return isFreebuffDeploymentHours(now)
 }
 
+/**
+ * The window to quote when `model` is refused for being unavailable.
+ *
+ * Derived from the model's OWN availability instead of assumed. Both refusal
+ * sites in free-session/public-api.ts gate on isFreebuffSessionModelAvailable,
+ * which covers `deployment_hours` AND `off_peak_only`, but both hardcoded the
+ * deployment-hours label -- so a model closed for DeepSeek's peak window was
+ * quoted our staffing hours, a different window entirely.
+ */
+export function freebuffModelUnavailableWindow(
+  id: string,
+  now: Date = new Date(),
+): string {
+  const model =
+    SUPPORTED_FREEBUFF_MODELS.find((candidate) => candidate.id === id) ??
+    getFreebuffWebModel(id)
+  return model.availability === 'off_peak_only'
+    ? formatDeepSeekExpensiveWindowReturn(now)
+    : FREEBUFF_DEPLOYMENT_HOURS_LABEL
+}
+
 export function isFreebuffSessionModelAvailable(
   id: string,
   now: Date = new Date(),

common/src/constants/freebuff-peak-hours.ts

@@ -124,3 +124,30 @@ export function formatDeepSeekExpensiveWindowLocal(
   const [start, end] = DEEPSEEK_EXPENSIVE_WINDOW_UTC
   return `${atUtcHour(start)} – ${atUtcHour(end)}`
 }
+
+/**
+ * What to tell a user whose model is shut for the peak window.
+ *
+ * Phrased as WHEN IT COMES BACK rather than as a range, because that is the
+ * question being asked. A range makes the reader do arithmetic against a clock
+ * they cannot see -- and the range this replaced was not even the right window:
+ * `model_unavailable` hardcoded FREEBUFF_DEPLOYMENT_HOURS_LABEL ("9am ET-5pm PT
+ * every day"), which describes OUR STAFFING hours for limited-offer models and
+ * has nothing to do with DeepSeek's peak pricing. A model closed 5pm-3am
+ * Pacific was telling people it was open 9am-5pm.
+ *
+ * Local time, and one timezone. The old label mixed two ("9am ET-5pm PT"),
+ * which cannot be read as an interval by anyone.
+ */
+export function formatDeepSeekExpensiveWindowReturn(
+  on: Date = new Date(),
+  timeZone?: string,
+): string {
+  const ends = deepSeekExpensiveWindowEndsAt(on)
+  const fmt = new Intl.DateTimeFormat(undefined, {
+    hour: 'numeric',
+    minute: '2-digit',
+    ...(timeZone ? { timeZone } : {}),
+  })
+  return `again at ${fmt.format(ends)}`
+}