fix(adapters): neutralize Codex CLI 0.145 identity wording (#638)

* fix(adapters): neutralize Codex CLI 0.145 identity wording

Closes #622

* fix(adapters): consume full GPT-5.x.y identity versions

Author: Wibias

src/adapters/identity.ts

@@ -14,9 +14,19 @@
  * to be a specific first-party client.
  */
 
-/** The exact identity line Codex injects for every model. */
+/** Historical exact identity line Codex injected for every model. */
 export const CODEX_GPT5_IDENTITY_LINE = "You are Codex, a coding agent based on GPT-5.";
 
+/** Codex CLI 0.145.0+ wording (#622) — still GPT-5 identity, slightly different phrasing. */
+export const CODEX_GPT5_IDENTITY_LINE_AGENT = "You are Codex, an agent based on GPT-5.";
+
+/**
+ * Known Codex GPT-5 identity sentences. Narrow: only "coding agent" / "an agent" + GPT-5(.x)?
+ * Avoid a broad `You are Codex.*` rewrite that could touch unrelated content.
+ */
+const CODEX_GPT5_IDENTITY_RE =
+  /You are Codex, (?:a coding agent|an agent) based on GPT-5(?:\.[0-9]+)*\./g;
+
 /** Proxy-neutral replacement: no "opencodex proxy" mention, just the GPT-5/OpenAI disclaimer. */
 export const NEUTRAL_IDENTITY_LINE = "You are a coding agent. Do not claim to be GPT-5 or to be made by OpenAI.";
 
@@ -27,7 +37,7 @@ export const NEUTRAL_IDENTITY_LINE = "You are a coding agent. Do not claim to be
  * the leak can't reappear in one adapter while being fixed in another.
  */
 export function neutralizeIdentity(systemText: string): string {
-  return systemText.replace(CODEX_GPT5_IDENTITY_LINE, NEUTRAL_IDENTITY_LINE);
+  return systemText.replace(CODEX_GPT5_IDENTITY_RE, NEUTRAL_IDENTITY_LINE);
 }
 
 /** The catalog (static, on-disk) replacement for `base_instructions`. Same neutral wording. */

tests/identity-neutralize.test.ts

@@ -2,7 +2,12 @@ import { afterEach, beforeEach, describe, expect, test } from "bun:test";
 import { mkdtempSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { CODEX_GPT5_IDENTITY_LINE, NEUTRAL_IDENTITY_LINE, neutralizeIdentity } from "../src/adapters/identity";
+import {
+  CODEX_GPT5_IDENTITY_LINE,
+  CODEX_GPT5_IDENTITY_LINE_AGENT,
+  NEUTRAL_IDENTITY_LINE,
+  neutralizeIdentity,
+} from "../src/adapters/identity";
 import { createGoogleAdapter } from "../src/adapters/google";
 import { createKiroAdapter } from "../src/adapters/kiro";
 import { createOpenAIChatAdapter } from "../src/adapters/openai-chat";
@@ -23,6 +28,12 @@ describe("identity neutralization — central helper", () => {
     expect(neutralizeIdentity(SYS)).toBe(NEUTRAL_IDENTITY_LINE);
   });
 
+  test("replaces the Codex CLI 0.145 'an agent' identity variant (#622)", () => {
+    expect(neutralizeIdentity(CODEX_GPT5_IDENTITY_LINE_AGENT)).toBe(NEUTRAL_IDENTITY_LINE);
+    expect(neutralizeIdentity("You are Codex, an agent based on GPT-5.4.")).toBe(NEUTRAL_IDENTITY_LINE);
+    expect(neutralizeIdentity("You are Codex, an agent based on GPT-5.4.1.")).toBe(NEUTRAL_IDENTITY_LINE);
+  });
+
   test("never emits the opencodex proxy identity", () => {
     const out = neutralizeIdentity(`${SYS}\n\nmore context`);
     expect(out).not.toMatch(/opencodex proxy/i);
@@ -32,6 +43,9 @@ describe("identity neutralization — central helper", () => {
 
   test("leaves text without the GPT-5 line unchanged", () => {
     expect(neutralizeIdentity("plain system text")).toBe("plain system text");
+    expect(neutralizeIdentity("You are Codex, helpful for reviewing PRs.")).toBe(
+      "You are Codex, helpful for reviewing PRs.",
+    );
   });
 
   test("neutral line still forbids GPT-5 / OpenAI self-reporting", () => {