OpenCode Configuration

The OpenCode GUI client uses the OpenAI-compatible chat/completions protocol. After pointing a custom provider to 4AICode, you can use models such as gpt-6-astra, gpt-5.6-sol, gpt-5.5, gpt-5.4, gpt-5.4-mini, and gpt-5.3-codex in OpenCode.

Prerequisites

• 4AICode token: Create one in Dashboard → Manage Tokens. The format is sk-4ai-...
• Provider ID: 4aicode
• Base URL: https://relay.4aicode.com/v1
• Default model: gpt-5.4
• Code model: gpt-5.3-codex

GUI Client Configuration

Open the gear settings in the lower-left corner, go to the Provider / Models configuration page, and add an OpenAI-compatible or Custom provider.

Fill in the interface fields as follows:

After saving, return to the main interface and select the following in the model picker at the bottom:

4AICode / GPT-5.4

Then create a new conversation and send:

Hello

If it responds normally, the GUI configuration is complete.

Timeout Errors Shown in the GUI

When you see an error like the following, focus on checking the timeout fields in the GUI:

Provider response headers timed out after 10000ms

This means the OpenCode GUI timed out while waiting for the provider response headers. The first response chunk from the Codex upstream may occasionally take longer than 10 seconds, so increase the timeout values in the GUI advanced settings:

If your GUI version does not provide timeout input fields, use the opencode.json method below to add them.

Configuration File Method

Suitable for GUI versions where timeout values cannot be entered directly. Create or edit:

~/.config/opencode/opencode.json

Add:

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "4aicode": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "4AICode",
      "options": {
        "baseURL": "https://relay.4aicode.com/v1",
        "apiKey": "sk-4ai-xxxxxxxxxxxxxxxx",
        "timeout": 600000,
        "chunkTimeout": 120000
      },
      "models": {
        "gpt-6-astra": {
          "name": "GPT-6 Astra"
        },
        "gpt-5.6-sol": {
          "name": "GPT-5.6 Sol"
        },
        "gpt-5.6-terra": {
          "name": "GPT-5.6 Terra"
        },
        "gpt-5.6-luna": {
          "name": "GPT-5.6 Luna"
        },
        "gpt-5.5": {
          "name": "GPT-5.5"
        },
        "gpt-5.4": {
          "name": "GPT-5.4"
        },
        "gpt-5.4-mini": {
          "name": "GPT-5.4 Mini"
        },
        "gpt-5.3-codex": {
          "name": "GPT-5.3 Codex"
        }
      }
    }
  },
  "model": "4aicode/gpt-5.4",
  "small_model": "4aicode/gpt-5.4-mini"
}

After restarting the OpenCode GUI, select 4AICode / GPT-5.4 in the model picker.

Add Credentials Interactively

Enter your project directory and start OpenCode:

opencode

Run the following in OpenCode:

/connect

Select and enter the following as prompted:

Provider: Other
Provider ID: 4aicode
API key: sk-4ai-xxxxxxxxxxxxxxxx

Then create or edit opencode.json in the project root directory, using the content from the “Configuration File Method” section above as a reference.

Return to OpenCode and run:

/models

Select a model under 4AICode.

Environment Variable Method

Store the token in an environment variable. This is suitable for sharing opencode.json across a team.

export FOURAICODE_API_KEY="sk-4ai-xxxxxxxxxxxxxxxx"

opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "4aicode": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "4AICode",
      "options": {
        "baseURL": "https://relay.4aicode.com/v1",
        "apiKey": "{env:FOURAICODE_API_KEY}",
        "timeout": 600000,
        "chunkTimeout": 120000
      },
      "models": {
        "gpt-6-astra": {
          "name": "GPT-6 Astra"
        },
        "gpt-5.6-sol": {
          "name": "GPT-5.6 Sol"
        },
        "gpt-5.6-terra": {
          "name": "GPT-5.6 Terra"
        },
        "gpt-5.6-luna": {
          "name": "GPT-5.6 Luna"
        },
        "gpt-5.5": {
          "name": "GPT-5.5"
        },
        "gpt-5.4": {
          "name": "GPT-5.4"
        },
        "gpt-5.4-mini": {
          "name": "GPT-5.4 Mini"
        },
        "gpt-5.3-codex": {
          "name": "GPT-5.3 Codex"
        }
      }
    }
  },
  "model": "4aicode/gpt-5.4",
  "small_model": "4aicode/gpt-5.4-mini"
}

Global Configuration Paths

Place user-level configuration here:

~/.config/opencode/opencode.json

Place project-level configuration in the project root:

opencode.json

Project-level configuration takes precedence and is suitable for pinning a provider and model for a specific code repository.

Available Models

Use the full OpenCode format for model fields, for example, 4aicode/gpt-5.3-codex. The display name in the interface can be GPT-5.3 Codex.

FAQ

Provider response headers timed out after 10000ms

This means the OpenCode GUI timed out while waiting for the provider response headers. The first response chunk from the Codex upstream may occasionally take longer than 10 seconds. Increase timeout and chunkTimeout in the configuration:

{
  "provider": {
    "4aicode": {
      "options": {
        "baseURL": "https://relay.4aicode.com/v1",
        "timeout": 600000,
        "chunkTimeout": 120000
      }
    }
  }
}

Then send Hello using gpt-5.4-mini for a quick connectivity test. After confirming connectivity, switch back to gpt-5.4 or gpt-5.3-codex.

401 Unauthorized

The API key has expired or was copied incorrectly. Create a new token in Dashboard → Manage Tokens, then update the /connect credentials or environment variable.

400 Model Not Supported

Use the literal model IDs listed in the table. Common choices are 4aicode/gpt-5.4 and 4aicode/gpt-5.3-codex.

The Model List Does Not Appear After Configuration

Check these three items:

• The Provider ID entered in /connect is 4aicode
• The provider key in opencode.json is "4aicode"
• model uses the full format, such as 4aicode/gpt-5.4

References

• OpenCode Providers
• OpenCode Config