fix(codex): prefer native tokens for resume budget

Han Kim · Han Kim · commit 147b9a9fd8c5 · 2026-05-17T11:21:50.000-07:00
diff --git a/extensions/codex/src/app-server/run-attempt.test.ts b/extensions/codex/src/app-server/run-attempt.test.ts
@@ -6204,6 +6204,65 @@ describe("runCodexAppServerAttempt", () => {
     expect(savedBinding?.threadId).toBe("thread-1");
   });
 
+  it("resumes a bound Codex thread when stale mirrored token totals remain over budget", async () => {
+    const sessionFile = path.join(tempDir, "session.jsonl");
+    const workspaceDir = path.join(tempDir, "workspace");
+    const agentDir = path.join(tempDir, "agent");
+    await writeExistingBinding(sessionFile, workspaceDir, { dynamicToolsFingerprint: "[]" });
+    await fs.writeFile(
+      path.join(path.dirname(sessionFile), "sessions.json"),
+      JSON.stringify({
+        "agent:main:session-1": {
+          sessionFile,
+          totalTokens: 96_000,
+        },
+      }),
+    );
+    const rolloutDir = path.join(agentDir, "codex-home", "sessions");
+    await fs.mkdir(rolloutDir, { recursive: true });
+    await fs.writeFile(
+      path.join(rolloutDir, "rollout-thread-existing.jsonl"),
+      `${JSON.stringify({
+        payload: {
+          type: "token_count",
+          info: {
+            total_token_usage: {
+              total_tokens: 97_000,
+            },
+            last_token_usage: {
+              total_tokens: 12_000,
+            },
+          },
+        },
+      })}\n`,
+    );
+    const { requests, waitForMethod, completeTurn } = createResumeHarness();
+    const params = createParams(sessionFile, workspaceDir);
+    params.agentDir = agentDir;
+    params.config = {
+      agents: {
+        defaults: {
+          compaction: {
+            truncateAfterCompaction: true,
+            maxActiveTranscriptBytes: "1mb",
+          },
+        },
+      },
+    } as never;
+
+    const run = runCodexAppServerAttempt(params, {
+      pluginConfig: { appServer: { mode: "yolo" } },
+    });
+    await waitForMethod("turn/start");
+    await completeTurn({ threadId: "thread-existing", turnId: "turn-1" });
+    await run;
+
+    expect(requests.map((entry) => entry.method)).toContain("thread/resume");
+    expect(requests.map((entry) => entry.method)).not.toContain("thread/start");
+    const savedBinding = await readCodexAppServerBinding(sessionFile);
+    expect(savedBinding?.threadId).toBe("thread-existing");
+  });
+
   it("preserves bound auth when rotating an over-budget native rollout", async () => {
     const sessionFile = path.join(tempDir, "session.jsonl");
     const workspaceDir = path.join(tempDir, "workspace");
diff --git a/extensions/codex/src/app-server/run-attempt.ts b/extensions/codex/src/app-server/run-attempt.ts
@@ -705,7 +705,7 @@ async function rotateOversizedCodexAppServerStartupBinding(params: {
     Number.isFinite(sessionRecord.totalTokens)
       ? sessionRecord.totalTokens
       : undefined;
-  const tokenCount = maxFiniteNumber([sessionTokens, nativeTokens]);
+  const tokenCount = nativeTokens ?? sessionTokens;
   if (tokenCount !== undefined && tokenCount >= CODEX_APP_SERVER_NATIVE_THREAD_MAX_TOKENS) {
     embeddedAgentLog.warn(
       "codex app-server native transcript exceeded active token limit; starting a fresh thread",
