alt-glitch 85546bb9e2 gateway: capture real provider-reported cost (openrouter usage accounting)
Cost displays were estimates from a pricing table; on OpenRouter the
status bar never reflected what was actually charged. Now cost is
provider-REPORTED only, end to end:

- OpenRouter requests carry usage:{include:true} (profile + legacy
  transport paths); the response usage.cost field (credits, 1:1 USD)
  is captured per call into agent.session_actual_cost_usd and
  persisted to the sessions DB actual_cost_usd column (NULL-safe:
  unreported calls never touch the stored value).
- Nous keeps its x-nous-credits-* header capture; the header delta
  now surfaces as the session's real cost via real_session_cost_usd.
- Providers that report nothing accumulate NOTHING: cost fields stay
  absent/None (the TUI hides its cost segment), never a fabricated
  $0.00 and never an estimate. _get_usage, gateway /usage and the
  CLI usage page all switched off estimate_usage_cost for display.
- Per-model session accumulator (session_model_usage) records real
  per-call counts and provider-reported cost per model.
2026-06-11 00:14:21 +05:30
..

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.