Your first config

A minimal coulisse.yaml has two things: a provider (where to send model calls) and an agent (how to call it).

providers:
  anthropic:
    api_key: sk-ant-your-key-here

agents:
  - name: assistant
    provider: anthropic
    model: claude-sonnet-4-5-20250929
    preamble: You are a helpful assistant.

Save this as coulisse.yaml in your working directory, then run coulisse.

What each piece does

providers

A map of provider kind → credentials. The key must be one of the supported kinds (see Providers). You only need to list the providers you actually use.

agents

A list of agents. Each agent is a named recipe:

• name — the identifier. Clients ask for the agent by this name via the model field in their request.
• provider — which configured provider to route to.
• model — the upstream model identifier to call (e.g. claude-sonnet-4-5-20250929, gpt-4o).
• preamble — optional system prompt prepended to every conversation.

You can define as many agents as you want — see Multi-agent routing for what that unlocks.

Adding more

Want a code reviewer, a pirate, and a tool-using agent? Just add more entries:

providers:
  anthropic:
    api_key: sk-ant-...
  openai:
    api_key: sk-...

agents:
  - name: assistant
    provider: anthropic
    model: claude-sonnet-4-5-20250929
    preamble: You are a helpful assistant.

  - name: code-reviewer
    provider: anthropic
    model: claude-sonnet-4-5-20250929
    preamble: |
      You are a thorough code reviewer. Focus on correctness,
      clarity, and security.

  - name: gpt-assistant
    provider: openai
    model: gpt-4o
    preamble: You are a helpful assistant.

Restart the server — all three agents are now selectable by model name.

Next: make a request.