Hermes Agent

Hermes keeps providers in ~/.hermes/config.yaml under custom_providers, and selects one in the model block.

Configure

custom_providers:
  - name: routemux
    base_url: https://api.routemux.com/v1
    key_env: ROUTEMUX_API_KEY
    api_mode: chat_completions
    default_model: openai/gpt-5.5
    models:
      openai/gpt-5.5:
        name: GPT-5.5

model:
  provider: custom:routemux
  default: openai/gpt-5.5
  base_url: https://api.routemux.com/v1

export ROUTEMUX_API_KEY="sk-..."

A custom provider is referenced as custom:<name> — the custom: prefix is required. key_env points at an environment variable; use api_key instead if you want the value inline.

hermes model walks you through the same settings interactively, and hermes doctor reports providers it cannot resolve.

Protocol modes

api_mode selects the wire protocol:

Claude models are only available on anthropic_messages; Grok models are not available on it at all. See the compatibility matrix for the full picture.

Hermes normalises a trailing /v1 on the base URL, so https://api.routemux.com/v1 is the form to use throughout and you do not need a different value per mode.

Model ids

Use exactly what GET /v1/models returns, including the provider prefix. The models map keys are those ids; the name underneath is only a display label.

Troubleshooting