Arcadi4 Configuring OpenCode Custom Providers
This skill guides you on how to configure custom providers for OpenCode.
Before You Begin
The user must provide one or multiple pairs of provider API base url and API key. If they didn't, do nothing and ask the user to provide them.
What is OpenCode
OpenCode is an open-source coding agent. It relies on https://models.dev (Repo) to provide a catalogue of available models and providers, which is also maintained by Anomaly.
The Workflow
1. Locate the config file
Use opencode debug paths. If this fails, stop immediately.
2. Discover models from provided APIs
Fetch each provider API base url with the provided API key:
curl -H "Authorization: Bearer <API_KEY>" <API_BASE_URL>/v1/models
curl -H "x-api-key: <API_KEY>" <API_BASE_URL>/v1/models
If both returns 404, first retry without v1. If 404 persists, this might mean the API does not provide a models endpoint. You should ask the user to provide a model list instead before proceeding. Report accordingly if the error is not 404 (e.g., permission denied).
3. Get metadata of seen models
First, fetch <models.dev>'s API: https://models.dev/models.json. The JSON is extremely large, never curl is barely. You must gate the output through jq first. Then, for each model seen in the previous step, check if it exists in <models.dev>. If it does, get the metadata of the model. Model IDs from <models.dev> and the custom provider does not have to match exactly. You are allowed to make reasonable inferences.
If you cannot find a model on <models.dev>, do not add it to the config file in the next step. Report the models you cannot determine to the user in the final task report.
4. Determine API type
This determines the npm field to use. Try POST on /v1/chat/completions and /v1/messages WITHOUT keys (otherwise you might spend the user's API quota). If /v1/chat/completions exists, the API is OpenAI-style, use @ai-sdk/openai-compatible. If /v1/messages exists, the API is Anthropic-style, use @ai-sdk/anthropic. If both are available or both fails, prefer @ai-sdk/openai-compatible. In the case of failure, you should include this is the task report.
5. Edit the config file
Read these docs before you start, they will tell you the shape of custom providers and models configuration: https://opencode.ai/docs/providers https://opencode.ai/docs/models. Then, write the config file with valid models, and fill in the metadata with the information you got from <models.dev>. Note that you must use the id from the custom provider, not the id from <models.dev>.