OpenCode Go, the model does not support FIM

[kanagawa6]

Description

zed-industries/zed#56379

• The above is the problem I'm encountering when using the OpenCode Go API with the edit_predictions feature of the Zed Editor.
• Could you please help me review the last comment and resolve it?

Plugins

No response

OpenCode version

v1.14.48

Steps to reproduce

• Use Zed Editor and OpenCode Go with the following configuration:

{
  "edit_predictions": {
    "allow_data_collection": "no",
    "mode": "subtle",
    "provider": "open_ai_compatible_api",
    "open_ai_compatible_api": {
      "api_url": "https://opencode.ai/zen/go/v1/chat/completions",
      "model": "deepseek-v4-flash",
      "prompt_format": "deepseek_coder"
    }
  },
  "show_edit_predictions": true
}

• I used OpenCode Go to reduce the cost of the edit_predictions feature in Zed Editor.
• After using it, I received the following error:

2026-05-11T16:52:49+07:00 ERROR [crates/edit_prediction/src/edit_prediction.rs:2213] fim edit prediction failed: custom server error: 400 Bad Request - {"error":{"message":"Error from provider (DeepSeek): Failed to deserialize the JSON body into the target type: missing field `messages` at line 1 column 1335","type":"invalid_request_error","param":null,"code":"invalid_request_error"}}

• The programmers at Zed Editor want me to ask the publisher of OpenCode Go.

Screenshot and/or share link

No response

Operating System

Windows 10.0.19044

Terminal

Zed Editor + ACP

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• Steps to reproduce is empty — please describe how to reproduce the issue directly in this issue rather than linking only to an external issue tracker
• The description relies entirely on an external link; please summarize the problem here so it can be understood without following the link

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of an existing issue. Please check:

• OpenCode Go is not compatible with FIM. #26851: "OpenCode Go is not compatible with FIM." — same author, same description, and same external link

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Thanks for updating the issue! It now has all the required information and looks good. We appreciate you providing the reproduction steps, error log, and configuration details.

[kanagawa6]

@fwang can u help me?