opencode

Overview ¶

Package opencode implements a genai provider backed by the OpenCode CLI.

Instead of making HTTP requests directly, it launches `opencode acp` as a subprocess and communicates over stdin/stdout using the ACP (Agent Client Protocol) JSON-RPC 2.0 protocol.

See https://opencode.ai for OpenCode documentation and https://agentclientprotocol.com for the ACP specification.

Protocol ¶

The provider performs a JSON-RPC handshake (initialize → session/new) on each call, then sends a session/prompt request and reads session/update notifications until the session/prompt response arrives.

Session / multi-turn ¶

Each GenSync or GenStream call launches a fresh subprocess. The session ID is always returned inside Reply.Opaque["session_id"]. When the message history contains a previous session ID, it is automatically picked up: session/load is used instead of session/new and only the last user message is sent.

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/maruel/genai"
	"github.com/maruel/genai/providers/opencode"
)

func main() {
	c, err := opencode.New(genai.ProviderOptionModel("opencode/big-pickle"))
	if err != nil {
		log.Fatal(err)
	}
	res, err := c.GenSync(context.Background(), genai.Messages{genai.NewTextMessage("Say hello")})
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(res.Replies[0].Text)
}

Output: