feat(codex): add gpt-5.5 and wire live model discovery into picker (#14720)

OpenAI launched GPT-5.5 on Codex today (Apr 23 2026). Adds it to the static
catalog and pipes the user's OAuth access token into the openai-codex path of
provider_model_ids() so /model mid-session and the gateway picker hit the
live ChatGPT codex/models endpoint — new models appear for each user
according to what ChatGPT actually lists for their account, without a Hermes
release.

Verified live: 'gpt-5.5' returns priority 0 (featured) from the endpoint,
400k context per OpenAI's launch article. 'hermes chat --provider
openai-codex --model gpt-5.5' completes end-to-end.

Changes:
- hermes_cli/codex_models.py: add gpt-5.5 to DEFAULT_CODEX_MODELS + forward-compat
- agent/model_metadata.py: 400k context length entry
- hermes_cli/models.py: resolve codex OAuth token before calling
  get_codex_model_ids() in provider_model_ids('openai-codex')

agent/model_metadata.py

@@ -123,6 +123,9 @@ DEFAULT_CONTEXT_LENGTHS = {
     "claude": 200000,
     # OpenAI — GPT-5 family (most have 400k; specific overrides first)
     # Source: https://developers.openai.com/api/docs/models
+    # GPT-5.5 (launched Apr 23 2026). Verified via live ChatGPT codex/models
+    # endpoint: bare slug `gpt-5.5`, no -pro/-mini variants. 400k context on Codex.
+    "gpt-5.5": 400000,
     "gpt-5.4-nano": 400000,           # 400k (not 1.05M like full 5.4)
     "gpt-5.4-mini": 400000,           # 400k (not 1.05M like full 5.4)
     "gpt-5.4": 1050000,               # GPT-5.4, GPT-5.4 Pro (1.05M context)

hermes_cli/codex_models.py

@@ -12,6 +12,7 @@ import os
 logger = logging.getLogger(__name__)
 
 DEFAULT_CODEX_MODELS: List[str] = [
+    "gpt-5.5",
     "gpt-5.4-mini",
     "gpt-5.4",
     "gpt-5.3-codex",
@@ -21,6 +22,7 @@ DEFAULT_CODEX_MODELS: List[str] = [
 ]
 
 _FORWARD_COMPAT_TEMPLATE_MODELS: List[tuple[str, tuple[str, ...]]] = [
+    ("gpt-5.5", ("gpt-5.4", "gpt-5.4-mini", "gpt-5.3-codex")),
     ("gpt-5.4-mini", ("gpt-5.3-codex", "gpt-5.2-codex")),
     ("gpt-5.4", ("gpt-5.3-codex", "gpt-5.2-codex")),
     ("gpt-5.3-codex", ("gpt-5.2-codex",)),

hermes_cli/models.py

@@ -1678,7 +1678,19 @@ def provider_model_ids(provider: Optional[str], *, force_refresh: bool = False)
     if normalized == "openai-codex":
         from hermes_cli.codex_models import get_codex_model_ids
 
-        return get_codex_model_ids()
+        # Pass the live OAuth access token so the picker matches whatever
+        # ChatGPT lists for this account right now (new models appear without
+        # a Hermes release). Falls back to the hardcoded catalog if no token
+        # or the endpoint is unreachable.
+        access_token = None
+        try:
+            from hermes_cli.auth import resolve_codex_runtime_credentials
+
+            creds = resolve_codex_runtime_credentials(refresh_if_expiring=True)
+            access_token = creds.get("api_key")
+        except Exception:
+            access_token = None
+        return get_codex_model_ids(access_token=access_token)
     if normalized in {"copilot", "copilot-acp"}:
         try:
             live = _fetch_github_models(_resolve_copilot_catalog_api_key())