[codex] fix empty stream success handling and unknown usage logs (#343)

* fix: preserve repeated short responses deltas

* fix empty stream success handling and unknown usage logs

* fix proxy usage metadata typing

* fix stream bookkeeping and explicit zero usage source

* fix sticky fast path and usage placeholder detection

src/server/routes/api/stats.proxy-logs.test.ts

@@ -534,4 +534,54 @@ describe('stats proxy logs routes', () => {
     expect(detailBody.clientAppId).toBe(null);
     expect(detailBody.clientAppName).toBe(null);
   });
+
+  it('returns unknown usage source and nullable token fields for logs without recovered usage', async () => {
+    const site = await db.insert(schema.sites).values({
+      name: 'unknown-usage-site',
+      url: 'https://unknown-usage.example.com',
+      platform: 'new-api',
+    }).returning().get();
+
+    const account = await db.insert(schema.accounts).values({
+      siteId: site.id,
+      username: 'unknown-usage-user',
+      accessToken: 'unknown-usage-token',
+      status: 'active',
+    }).returning().get();
+
+    await db.insert(schema.proxyLogs).values({
+      accountId: account.id,
+      modelRequested: 'gpt-5',
+      modelActual: 'gpt-5',
+      status: 'success',
+      promptTokens: null,
+      completionTokens: null,
+      totalTokens: null,
+      estimatedCost: 0,
+      errorMessage: '[downstream:/v1/chat/completions] [upstream:/v1/chat/completions] [usage:unknown]',
+      createdAt: formatUtcSqlDateTime(new Date('2026-03-09T12:30:00.000Z')),
+    }).run();
+
+    const response = await app.inject({
+      method: 'GET',
+      url: '/api/stats/proxy-logs',
+    });
+
+    expect(response.statusCode).toBe(200);
+    const body = response.json() as {
+      items: Array<{
+        usageSource: string | null;
+        promptTokens: number | null;
+        completionTokens: number | null;
+        totalTokens: number | null;
+      }>;
+    };
+
+    expect(body.items[0]).toMatchObject({
+      usageSource: 'unknown',
+      promptTokens: null,
+      completionTokens: null,
+      totalTokens: null,
+    });
+  });
 });

src/server/routes/api/stats.ts

@@ -275,6 +275,14 @@ function resolveProxyLogClientMeta(proxyLog: Record<string, unknown>) {
   };
 }
 
+function normalizeProxyLogUsageSource(value: unknown): 'upstream' | 'self-log' | 'unknown' | null {
+  const normalized = normalizeNullableText(value)?.toLowerCase() || null;
+  if (normalized === 'upstream' || normalized === 'self-log' || normalized === 'unknown') {
+    return normalized;
+  }
+  return null;
+}
+
 function buildProxyLogClientOptions(rows: Array<{
   clientFamily?: string | null;
   clientAppId?: string | null;
@@ -472,6 +480,7 @@ function mapProxyLogRow(
   options?: { includeBillingDetails?: boolean },
 ) {
   const clientMeta = resolveProxyLogClientMeta(row.proxy_logs);
+  const legacyMeta = parseProxyLogMessageMeta(typeof row.proxy_logs.errorMessage === 'string' ? row.proxy_logs.errorMessage : '');
   return {
     ...row.proxy_logs,
     ...(options?.includeBillingDetails
@@ -481,6 +490,7 @@ function mapProxyLogRow(
     clientAppId: clientMeta.clientAppId,
     clientAppName: clientMeta.clientAppName,
     clientConfidence: clientMeta.clientConfidence,
+    usageSource: normalizeProxyLogUsageSource(legacyMeta.usageSource),
     username: row.accounts?.username || null,
     siteId: row.sites?.id || null,
     siteName: row.sites?.name || null,