fix(codex): strip cli banner before output parsing

Author: roninjin10

src/agents/CodexAgent.ts

@@ -106,6 +106,11 @@ export class CodexAgent extends BaseCliAgent {
       args,
       stdin: fullPrompt,
       outputFile,
+      stdoutBannerPatterns: [
+        // Codex CLI prints a startup banner like:
+        // "OpenAI Codex v0.99.0-alpha.13 (research preview)"
+        /^OpenAI Codex v[^\n]*$/gm,
+      ],
       cleanup: async () => {
         if (!this.opts.outputLastMessage) {
           await fs.rm(outputFile, { force: true }).catch(() => undefined);

tests/base-cli-agent-stdout-errors.test.ts

@@ -147,3 +147,19 @@ describe("BaseCliAgent banner handling (opt-in)", () => {
     expect(result.text).toBe("Here is the actual response from the model.");
   });
 });
+
+describe("BaseCliAgent Codex banner stripping (opt-in)", () => {
+  const codexBanner = /^OpenAI Codex v[^\n]*$/gm;
+
+  test("strips Codex startup banner and keeps JSON payload", async () => {
+    const content = [
+      "OpenAI Codex v0.99.0-alpha.13 (research preview)",
+      '{"tickets":[{"id":"t1"}]}',
+    ].join("\n");
+    const agent = new StdoutAgent(content, {
+      stdoutBannerPatterns: [codexBanner],
+    });
+    const result = await agent.generate({ prompt: "test" });
+    expect(result.text).toBe('{"tickets":[{"id":"t1"}]}');
+  });
+});