hermes - 💡(How to fix) Fix bug: _extract_pricing crashes on list-typed pricing values, causing context_length fallback to 256K [1 pull requests]

_extract_pricing() in agent/model_metadata.py crashes with TypeError: unhashable type: 'list' when a provider's /v1/models endpoint returns pricing values as lists of objects (e.g. zenmux.ai). This causes fetch_endpoint_model_metadata() to return an empty dict, which makes get_model_context_length() fall through to DEFAULT_FALLBACK_CONTEXT (256K) instead of the correct value — even when the endpoint clearly reports context_length: 1000000 and hardcoded defaults also specify 1M.

Root Cause

agent/model_metadata.py line 596:

python
if alias in normalized and normalized[alias] not in {None, ""}:


normalized[alias] can be a list (e.g. zenmux returns "completion": [{"value": 2, "unit": "perMTokens", ...}]). Lists are unhashable, so list not in {None, ""} raises TypeError.

This exception is caught by the outer except Exception in the candidate loop, which silently moves to the next candidate URL. When all candidates fail (the 2nd candidate /api/models returns HTML, not JSON), the function caches an empty dict and returns {}.

Impact

Any custom endpoint whose /v1/models response includes list-typed pricing fields will have its model metadata discarded. The function then exits early at the custom-endpoint branch with DEFAULT_FALLBACK_CONTEXT — the hardcoded defaults (step 8) and OpenRouter cache (step 6) are never reached because the custom-endpoint path has its own early-return fallback.

Reproduction

python
from agent.model_metadata import get_model_context_length

ctx = get_model_context_length(
    model='deepseek/deepseek-v4-pro',
    base_url='https://zenmux.ai/api/v1',
    api_key='<valid-zenmux-key>',
    provider='custom:zenmux',
)
Returns: 256000 (DEFAULT_FALLBACK_CONTEXT)
Expected: 1000000


Fix

One-line change — add a type guard before the membership check:

diff
-                if alias in normalized and normalized[alias] not in {None, ""}:
+                if alias in normalized and isinstance(normalized[alias], (int, float, str)) and normalized[alias] not in {None, ""}:


Environment

- Hermes Agent v0.13.0 (2026.5.7) and latest origin/main
- Python 3.11
- Reproduced with zenmux.ai