Model Provider Plugins

Each subdirectory is a self-contained provider profile plugin. The directory layout mirrors plugins/platforms/:

plugins/model-providers/
├── openrouter/
│   ├── __init__.py      # registers the ProviderProfile
│   └── plugin.yaml      # manifest: name, kind, version, description
├── anthropic/
│   ├── __init__.py
│   └── plugin.yaml
└── ...

How discovery works

providers/__init__.py._discover_providers() scans this directory (and $HERMES_HOME/plugins/model-providers/) the first time anything calls get_provider_profile() or list_providers(). Each __init__.py is imported and expected to call providers.register_provider(profile).

User plugins at $HERMES_HOME/plugins/model-providers/<name>/ override bundled plugins of the same name — last-writer-wins in register_provider(). Drop a file there to replace a built-in.

Adding a new provider

1. Create plugins/model-providers/<your_provider>/__init__.py:

   from providers import register_provider
   from providers.base import ProviderProfile
   
   my_provider = ProviderProfile(
       name="your-provider",
       aliases=("alias1", "alias2"),
       display_name="Your Provider",
       description="One-line description shown in the setup picker",
       signup_url="https://your-provider.example.com/keys",
       env_vars=("YOUR_PROVIDER_API_KEY", "YOUR_PROVIDER_BASE_URL"),
       base_url="https://api.your-provider.example.com/v1",
       default_aux_model="your-cheap-model",
   )
   
   register_provider(my_provider)
   

2. Create plugins/model-providers/<your_provider>/plugin.yaml:

   name: your-provider-profile
   kind: model-provider
   version: 1.0.0
   description: Short sentence about the provider
   author: Your Name
   

Nothing else needs to change. auth.py, config.py, models.py, doctor.py, model_metadata.py, runtime_provider.py, and the chat_completions transport all auto-wire from the registry.

Non-trivial profiles

Override the ProviderProfile hooks in a subclass for per-provider quirks — see plugins/model-providers/openrouter/__init__.py for build_extra_body and build_api_kwargs_extras examples, and plugins/model-providers/gemini/__init__.py for thinking_config translation.