Resource

session

Opaque handle to an active session.

resource session;

F prompt

prompt: async func(prompt: list<content-block>) -> result<prompt-response, error>;

Run a prompt turn to completion. Resolves with the terminal prompt-response when the turn ends. Intermediate session-updates are emitted via client.notify-session during the call.

To cancel, drop the future (or use the host's cancel machinery); the agent MUST resolve with stop-reason::cancelled.

See: https://agentclientprotocol.com/protocol/prompt-turn

F set-mode

set-mode: async func(mode-id: session-mode-id) -> result<_, error>;

Switch the active mode for this session. The mode-id MUST be one of the modes returned in the session's lifecycle response.

See: https://agentclientprotocol.com/protocol/session-modes

F select-model

select-model: async func(model-id: session-model-id) -> result<_, error>;

Switch the active model for this session. UNSTABLE. The model-id MUST be one of the models returned in the session's lifecycle response.

F set-config-option

set-config-option: async func(config-id: session-config-id, value: session-config-value-id) -> result<list<session-config-option>, error>;

Set a configuration option (model / mode / thought-level) for this session. The config-id and value MUST come from the option set advertised in the session's lifecycle response. Returns the full updated option set (mirroring the ACP session/set_config_option response).

See: https://agentclientprotocol.com/protocol/session-config