Model adapter

AgentAdapter is one method. openAICompatible is the built-in implementation.

interface AgentAdapter {
  generate(input: {
    messages: readonly Message[];
    tools: readonly ToolDefinition[];
    signal?: AbortSignal;
  }): Promise<AgentTurn>;
}

AgentTurn is { text: string; toolCalls: ToolCall[] }. Return an empty toolCalls array to end the turn with text.

openAICompatible

import { openAICompatible } from 'actionwire';

const model = openAICompatible({ endpoint: '/api/assistant' });

Option	Type	Meaning
endpoint	string	URL on your own origin that holds the API key.

It POSTs JSON with the transcript and the discovered tools in OpenAI chat-completions shape, and reads the tool calls out of the response. It never holds a key. See Model endpoint.

Tool names

Provider APIs restrict function names to [a-zA-Z0-9_-], up to 64 characters. The adapter maps each tool to a safe provider name and maps the response back to your real tool id. Your tool names are not limited by that rule.

Errors it raises

Situation	Code
Network failure, or a non-2xx status	MODEL_ERROR
Response body is not JSON	MODEL_ERROR
The request was aborted	ABORTED

The browser is told only that the turn failed. Read your server log for the provider's message. This is deliberate: provider errors can contain the prompt, and sometimes the key.

Writing an adapter

Use one when your provider does not speak the OpenAI shape, or when you want to add retries, logging, or a local model.

import { AgentError } from 'actionwire';
import type { AgentAdapter } from 'actionwire';

export function myModel(endpoint: string): AgentAdapter {
  return {
    async generate({ messages, tools, signal }) {
      const response = await fetch(endpoint, {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ messages, tools }),
        ...(signal === undefined ? {} : { signal }),
      });
      if (!response.ok) throw new AgentError('MODEL_ERROR', 'The model request failed.');
      const payload = await response.json();
      return { text: payload.text ?? '', toolCalls: payload.toolCalls ?? [] };
    },
  };
}

Rules:

• Honour signal. The bridge uses it for cancel() and for timeoutMs.
• Throw AgentError('ABORTED', …) on an abort, and MODEL_ERROR on anything else. Other exceptions surface as a generic failure.
• Every ToolCall you return needs a unique id, a toolId that matches a discovered tool, and an arguments object.
• Do not execute tools in the adapter. The bridge is the only execution path, and it is where confirmation happens.