Ox Alpha on OpenCode

Date: 2026-08-25

Status: Measured

You can reach the Ox Alpha model through OpenCode on two different endpoints: OpenCode Zen and OpenCode Go. The Zen version is unauthenticated and free. The Go version requires an OpenCode Go API key.

OpenCode Zen (unauthenticated)

OpenCode serves a free preview of Ox Alpha through its Zen gateway. You do not need an account or an API key.

The model ID is x-preview-f-free and the endpoint is:

POST https://opencode.ai/zen/v1/chat/completions

Example request:

curl -s -X POST https://opencode.ai/zen/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "x-preview-f-free",
    "messages": [
      {"role": "user", "content": "hi"}
    ],
    "stream": false
  }'

The public models list at https://opencode.ai/zen/v1/models also includes x-preview-f-free. A measured response returned cost: "0", so this is the cheapest way to try Ox Alpha when it is available.

Note that the model is a limited-time free preview. It is rate-limited by source IP and may become unavailable or change identifiers without notice.

OpenCode Go (authenticated)

The same model is also listed in OpenCode Go as ox-alpha-free. This version requires an OpenCode Go subscription and a workspace API key.

The model ID is ox-alpha-free and the endpoint is:

POST https://opencode.ai/zen/go/v1/chat/completions

Example request:

curl -s -X POST https://opencode.ai/zen/go/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer $OPENCODE_GO_API_KEY' \
  -d '{
    "model": "ox-alpha-free",
    "messages": [
      {"role": "user", "content": "hi"}
    ],
    "stream": false
  }'

The Go gateway parses the Authorization header as a Bearer token and looks up the key in the OpenCode console database. A missing, invalid, or exhausted key returns 401.

The public API key marker

The OpenCode CLI provider in packages/opencode/src/provider/provider.ts sets apiKey: "public" when it does not find a stored credential. This is not a real key. The OpenCode gateway explicitly ignores the string public and treats the request as unauthenticated. If the model does not allow anonymous access, the gateway returns 401 Missing API key.

Verification

The measurements in this document were made on 2026-08-25:

• GET https://opencode.ai/zen/v1/models returned x-preview-f-free without authentication.
• POST https://opencode.ai/zen/v1/chat/completions with x-preview-f-free returned a 200 completion with cost: "0" and no Authorization header.
• POST https://opencode.ai/zen/go/v1/chat/completions with ox-alpha-free returned 401 Missing API key.

Recheck the live endpoints before relying on these values in production.