OpenCode Free Tier returns 403 when used through 9Router

OpenCode free-tier models are currently returning HTTP 403 when accessed through 9Router.

The error returned is:

HTTP 403: [403]: {
  "type": "error",
  "error": {
    "type": "FreeTierError",
    "message": "Error from provider (Console): OpenCode's free tier can only be used from within OpenCode"
  }
}

It looks like OpenCode has changed or restricted its free-tier access so that free models can only be used directly from the OpenCode client.

Because 9Router acts as a proxy/router, requests to OpenCode free-tier models are now rejected.

Environment

• 9Router version: v0.5.75
• Deployment: Docker
• OS: Ubuntu
• API endpoint: /v1
• Provider: OpenCode
• Authentication: OpenCode account / free tier

Affected models

Examples:

mimo-v2.5-free
muse-spark-1.2-contributor-free

Potentially all OpenCode free-tier models are affected.

Steps to reproduce

1. Deploy 9Router v0.5.75
2. Login or configure OpenCode provider
3. Select an OpenCode free-tier model
4. Send a request through the 9Router OpenAI-compatible API
5. Request fails with HTTP 403

Example request flow:

Client / Hermes
      ↓
9Router
      ↓
OpenCode
      ↓
HTTP 403 FreeTierError

Actual behavior

The request fails with:

OpenCode's free tier can only be used from within OpenCode

Expected behavior

If OpenCode free-tier access is still supported by 9Router, requests should work normally.

If OpenCode no longer allows third-party/proxy access to free-tier models, 9Router should ideally:

• Detect this restriction
• Show a clearer error message in the UI
• Mark affected OpenCode free-tier models as unavailable
• Avoid repeatedly routing requests to an unusable free-tier endpoint
• Optionally fallback to another configured provider/model

Additional notes

This appears to be a provider-side restriction rather than a Docker, networking, or 9Router API configuration issue.

Paid OpenCode models or other providers may still work normally.

It would be useful to know whether:

1. OpenCode free-tier support can still be maintained in 9Router
2. Authentication or API behavior has changed
3. Free-tier models should be removed/disabled from the provider list
4. A fallback mechanism can be added when this specific FreeTierError occurs