fix(codex): provision dummy user auth state

bot_bottle/codex_auth.py

@@ -10,6 +10,7 @@ from __future__ import annotations
 import base64
 import json
 import os
+from copy import deepcopy
 from datetime import datetime, timezone
 from pathlib import Path
 
@@ -37,16 +38,12 @@ def codex_host_access_token(
             "Run `codex login --device-auth` on the host or disable "
             "agent_provider.forward_host_credentials."
         )
-    try:
-        raw = json.loads(path.read_text())
-    except (OSError, json.JSONDecodeError) as e:
-        die(f"codex host credentials: could not read valid JSON at {path}: {e}")
-    if not isinstance(raw, dict):
-        die(f"codex host credentials: {path} must contain a JSON object")
+    raw = _read_auth_object(path)
 
-    if raw.get("auth_mode") != "chatgpt":
+    auth_mode = raw.get("auth_mode")
+    if not isinstance(auth_mode, str) or auth_mode == "api_key":
         die(
-            "codex host credentials: host Codex auth is not ChatGPT/device "
+            "codex host credentials: host Codex auth is not user/device "
             "auth. Run `codex login --device-auth` on the host."
         )
 
@@ -72,6 +69,79 @@ def codex_host_access_token(
     return access
 
 
+def codex_dummy_auth_json(
+    host_env: dict[str, str] | None = None,
+    *,
+    now: datetime | None = None,
+) -> str:
+    """Return a non-secret `auth.json` that keeps Codex in the host's
+    auth branch while egress owns the real bearer token."""
+    path = codex_auth_path(host_env)
+    codex_host_access_token(host_env, now=now)
+    raw = _read_auth_object(path)
+    dummy = _redact_codex_auth(deepcopy(raw), now=now)
+    return json.dumps(dummy, indent=2, sort_keys=True) + "\n"
+
+
+def write_codex_dummy_auth_file(
+    path: Path,
+    host_env: dict[str, str] | None = None,
+    *,
+    now: datetime | None = None,
+) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(codex_dummy_auth_json(host_env, now=now))
+    path.chmod(0o600)
+
+
+def _read_auth_object(path: Path) -> dict:
+    try:
+        raw = json.loads(path.read_text())
+    except (OSError, json.JSONDecodeError) as e:
+        die(f"codex host credentials: could not read valid JSON at {path}: {e}")
+    if not isinstance(raw, dict):
+        die(f"codex host credentials: {path} must contain a JSON object")
+    return raw
+
+
+def _dummy_jwt(now: datetime | None = None) -> str:
+    check_now = now or datetime.now(timezone.utc)
+    exp = int(check_now.timestamp()) + 3600
+
+    def enc(obj: dict) -> str:
+        raw = json.dumps(obj, separators=(",", ":")).encode()
+        return base64.urlsafe_b64encode(raw).decode().rstrip("=")
+
+    return (
+        f"{enc({'alg': 'none', 'typ': 'JWT'})}."
+        f"{enc({'exp': exp, 'sub': 'bot-bottle-placeholder'})}."
+        "placeholder"
+    )
+
+
+def _redact_codex_auth(value: object, *, now: datetime | None = None) -> object:
+    if isinstance(value, dict):
+        out: dict[str, object] = {}
+        for key, inner in value.items():
+            lower = key.lower()
+            if lower == "openai_api_key":
+                out[key] = None
+            elif lower == "tokens":
+                out[key] = _redact_codex_auth(inner, now=now)
+            elif lower in {"access_token", "id_token"}:
+                out[key] = _dummy_jwt(now)
+            elif "token" in lower or "secret" in lower or lower.endswith("_key"):
+                out[key] = "bot-bottle-placeholder"
+            elif lower in {"account_id", "user_id", "email"}:
+                out[key] = "bot-bottle-placeholder"
+            else:
+                out[key] = _redact_codex_auth(inner, now=now)
+        return out
+    if isinstance(value, list):
+        return [_redact_codex_auth(v, now=now) for v in value]
+    return value
+
+
 def _jwt_exp(token: str) -> datetime | None:
     parts = token.split(".")
     if len(parts) < 2:
@@ -93,4 +163,9 @@ def _b64url_decode(value: str) -> str:
     return base64.urlsafe_b64decode(padded.encode("ascii")).decode("utf-8")
 
 
-__all__ = ["codex_auth_path", "codex_host_access_token"]
+__all__ = [
+    "codex_auth_path",
+    "codex_dummy_auth_json",
+    "codex_host_access_token",
+    "write_codex_dummy_auth_file",
+]