ACP: set_model is not implemented

[ignatov]

What happened?

When ACP-compatible client (e.g. JetBrains) called set_model, qwen failed

OUT: {"type":"com.agentclientprotocol.rpc.JsonRpcRequest","id":3,"method":"session/set_model","params":{"sessionId":"ee982ff7-70b0-4c98-b239-5a18b1059516","modelId":"coder-model"},"jsonrpc":"2.0"}

IN: {"jsonrpc":"2.0","id":3,"error":{"code":-32601,"message":"Method not found","data":{"details":"session/set_model"}}}

2026-01-05 17:04:35,842 [ 528944]   FINE - AcpTransport - OUT: {"type":"com.agentclientprotocol.rpc.JsonRpcRequest","id":1,"method":"initialize","params":{"protocolVersion":1,"clientCapabilities":{"fs":{"readTextFile":false,"writeTextFile":false},"terminal":false,"_meta":{"terminal-auth":true}}},"jsonrpc":"2.0"}
2026-01-05 17:04:44,106 [ 537208]   FINE - AcpTransport - IN: {"jsonrpc":"2.0","id":1,"result":{"protocolVersion":1,"agentInfo":{"name":"qwen-code","title":"Qwen Code","version":"0.6.0"},"authMethods":[{"id":"openai","name":"Use OpenAI API key","description":"Requires setting the `OPENAI_API_KEY` environment variable"},{"id":"qwen-oauth","name":"Qwen OAuth","description":"OAuth authentication for Qwen models with 2000 daily requests"}],"modes":{"currentModeId":"default","availableModes":[{"id":"plan","name":"Plan","description":"Analyze only, do not modify files or execute commands"},{"id":"default","name":"Default","description":"Require approval for file edits or shell commands"},{"id":"auto-edit","name":"Auto Edit","description":"Automatically approve file edits"},{"id":"yolo","name":"YOLO","description":"Automatically approve all tools"}]},"agentCapabilities":{"loadSession":true,"promptCapabilities":{"image":true,"audio":true,"embeddedContext":true}}}}
2026-01-05 17:04:44,112 [ 537214]   FINE - AcpTransport - OUT: {"type":"com.agentclientprotocol.rpc.JsonRpcRequest","id":2,"method":"session/new","params":{"cwd":"C:\\Users\\Anna.Zhdan\\IdeaProjects\\advent","mcpServers":[]},"jsonrpc":"2.0"}
2026-01-05 17:04:44,278 [ 537380]   FINE - AcpTransport - IN: {"jsonrpc":"2.0","id":2,"result":{"sessionId":"ee982ff7-70b0-4c98-b239-5a18b1059516","models":{"currentModelId":"coder-model","availableModels":[{"modelId":"coder-model","name":"coder-model","description":null,"_meta":{"contextLimit":1048576}}],"_meta":null}}}
2026-01-05 17:04:44,279 [ 537381]   FINE - AcpTransport - OUT: {"type":"com.agentclientprotocol.rpc.JsonRpcRequest","id":3,"method":"session/set_model","params":{"sessionId":"ee982ff7-70b0-4c98-b239-5a18b1059516","modelId":"coder-model"},"jsonrpc":"2.0"}
2026-01-05 17:04:44,313 [ 537415]   FINE - AcpTransport - IN: {"jsonrpc":"2.0","id":3,"error":{"code":-32601,"message":"Method not found","data":{"details":"session/set_model"}}}

What did you expect to happen?

Owen shouldn't fail

Client information

Client Information

Run qwen to enter the interactive CLI, then run the /about command.

$ qwen /about
# paste output here

Login information

No response

Anything else we need to know?

No response

[github-actions]

⚠️ Missing Required Information

Thank you for reporting this issue! To help us investigate and resolve this problem more effectively, we need some additional information:

• Qwen Code version
• operating system information
• full output of the /about command (recommended)

How to provide this information:

Please run the following command and paste the complete output:

qwen
# Then in the interactive CLI, run:
/about

The output should look like:

CLI Version             0.0.14
Git Commit              9a0cb64a
Model                   coder-model
Sandbox                 no sandbox
OS                      darwin
Auth Method             qwen-oauth

Once you provide this information, we'll be able to assist you better. Thank you! 🙏

[ignatov]

[tanzhenxin]

@ignatov Thanks for reporting this issue! I checked the ACP schema definition, and there is no officially defined session/set_model method. In fact, coder-model is already the default model when using Qwen OAuth, so there’s no need to set it manually.

[ignatov]

Hey @tanzhenxin!

It's experimental right now: export type SetSessionModelRequest https://github.com/agentclientprotocol/typescript-sdk/blob/ee94762f4947ac97fb7cb3af485db60722c276d9/src/schema/types.gen.ts#L2583

[tanzhenxin]

@ignatov That’s great! We’re planning to roll out the enhanced multi-provider model feature in the next major release (see #1291), and dynamic model switching will be an important capability for ACP once multiple models are supported. We’ll take a closer look at this soon.