OpenCode

OpenCode loads OpenAI-compatible providers through @ai-sdk/openai-compatible. It speaks Chat Completions, so the base URL is https://deference.si/v1. This guide uses the 1.x config format.

Set up

1. Create a key in API keys and export it as DEFERENCE_API_KEY in the shell that starts OpenCode.
2. Add the provider to opencode.json in your project, or to ~/.config/opencode/opencode.json for every project. On Windows the global file is %USERPROFILE%\.config\opencode\opencode.jsonc.

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "deference": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "Deference",
      "options": {
        "baseURL": "https://deference.si/v1",
        "apiKey": "{env:DEFERENCE_API_KEY}"
      },
      "models": {
        "anthropic/claude-sonnet-5.5": {
          "name": "Claude Sonnet 5.5",
          "limit": { "context": 200000, "output": 64000 }
        }
      }
    }
  },
  "model": "deference/anthropic/claude-sonnet-5.5"
}

3. Start opencode.

To store the key instead of reading it from the environment, run /connect, choose Other, enter the provider id deference and paste the key. OpenCode saves it in ~/.local/share/opencode/auth.json.

Verify

1. Run opencode models deference. It lists the models you declared.
2. Run a one-off prompt.

opencode run -m deference/anthropic/claude-sonnet-5.5 \
  "Reply with exactly: gateway-ok"

3. Open Activity. The request is the top row, with the model you chose.

opencode auth list shows keys saved with /connect. A key read from {env:DEFERENCE_API_KEY} does not appear there.

Pick a model

• List each model you want under models, keyed by its exact id. Select one with -m deference/<id>, the model setting, or /models.
• A model reference is provider/model. OpenCode splits on the first slash, so the model id can contain slashes.
• Set limit.context and limit.output for every model. OpenCode takes limits from a public registry for its built-in providers and has none for yours.
• Use @ai-sdk/openai as the package for models served through POST /v1/responses. You can set a different package on one model.
• OpenCode 2 renames some config fields. Keep to one format per file and follow OpenCode's migration guide when you move.

Troubleshooting