diff --git a/src/lib/oauth/crs-usage-probe.mjs b/src/lib/oauth/crs-usage-probe.mjs
index 90961052f..f62c078d8 100644
--- a/src/lib/oauth/crs-usage-probe.mjs
+++ b/src/lib/oauth/crs-usage-probe.mjs
@@ -135,7 +135,9 @@ export function parseOAuthUsage(data = {}) {
 
 export function isCompleteOAuthUsage(data = {}, parsed = null) {
   const p = parsed || parseOAuthUsage(data)
-  if (!p.five_hour || !p.seven_day) return false
+  // Official usage can omit the session window while retaining weekly limits.
+  // Keep an absent window unknown; a supplied but unreadable window is invalid.
+  if (!p.seven_day || (!p.five_hour && data.five_hour != null)) return false
   if (p.usage_has_fable !== null) return true
   // 2.1.293 GET /api/oauth/usage is a Utilization object: named windows, no limits[] catalog.
   if (
diff --git a/test/unit/crs-usage-probe.test.mjs b/test/unit/crs-usage-probe.test.mjs
index 150c2c50b..f72741cdb 100644
--- a/test/unit/crs-usage-probe.test.mjs
+++ b/test/unit/crs-usage-probe.test.mjs
@@ -2,6 +2,7 @@ import { test } from 'node:test'
 import assert from 'node:assert/strict'
 import {
   parseOAuthUsage,
+  isCompleteOAuthUsage,
   parseFableProbe,
   isFablePlanDenied,
   isFableUnavailablePro,
@@ -16,6 +17,25 @@ import {
   probeVmUsage,
 } from '../../src/lib/oauth/crs-usage-probe.mjs'
 
+test('official weekly-only usage is complete without inventing a session window', () => {
+  const data = {
+    five_hour: null,
+    seven_day: { utilization: 4, resets_at: '2026-11-05T12:00:00Z' },
+    limits: [{ kind: 'weekly_all', percent: 4, resets_at: '2026-11-05T12:00:00Z' }],
+  }
+  const parsed = parseOAuthUsage(data)
+  assert.equal(isCompleteOAuthUsage(data, parsed), true)
+  assert.equal(parsed.five_hour, null)
+  assert.equal(parsed.seven_day.utilization, 0.04)
+  const { five_hour, ...omitted } = data
+  assert.equal(isCompleteOAuthUsage(omitted), true)
+  assert.equal(isCompleteOAuthUsage({ ...data, five_hour: { utilization: 12 } }), true)
+  assert.equal(isCompleteOAuthUsage({ ...data, five_hour: {} }), false)
+  assert.equal(isCompleteOAuthUsage({ ...data, seven_day: null }), false)
+  assert.equal(isCompleteOAuthUsage({ five_hour: null, seven_day: null, limits: [] }), false)
+  assert.equal(isCompleteOAuthUsage({}), false)
+})
+
 test('oauth usage parse: official percent scale 1 = 1%', () => {
   const p = parseOAuthUsage({
     five_hour: { utilization: 1, resets_at: '2026-08-18T20:00:00Z' },