Go plan: 403 "An active OpenCode Go subscription is required" on every Go model — reproduced via API today, Zen models also 403 #52267

Description

A paid Go subscription ("Subscription Sep 2026", paid Sep 9 2026, $10) is shown as active on the billing page, but no Go model is served on this account since ~Sep 19. This is the same problem as #52098, which was closed by the compliance bot before the form could be filled in. This time everything is filled in and the failure is reproduced at the API level.

Reproduced today, 2026-09-30 12:39 MSK, with the account's Go key:

• GET https://opencode.ai/zen/go/v1/models -> 200, the model list is served
• POST https://opencode.ai/zen/go/v1/chat/completions with x-opencode-session -> 403 {"error":{"type":"server_error","message":"Upstream request failed: An active OpenCode Go subscription is required to use Go models."}} — same answer for glm-5.3-flash, gpt-5.6-luna, deepseek-v4-pro
• control on the same key: POST https://opencode.ai/zen/v1/chat/completions with gpt-5.4 -> 403 Model access is disabled

The key is accepted and routed, but the subscription is not applied to the account. In the client this looks like: every Go model returns 403 An active OpenCode Go subscription is required to use Go models, the "connect subscription" link opens the Console instead of linking the client, and usage that does go through is charged to the account balance instead of the plan.

Account m***@gmail.com (full address in #52098), workspace "Default".

Update 2026-09-30: the Go subscription is no longer listed on the Console dashboard at all — it has disappeared from the workspace, while the billing history still contains the September payment. The API behaviour above is unchanged (Go endpoints 403, non-Go endpoints 403 Model access is disabled), so the plan is simply not attached to the account any more.

Plugins

Not applicable to the API reproduction — the requests above are plain curl, no plugins.

OpenCode version

2.0.16 (client). The 403 above does not depend on the client version: it comes straight from the API.

Steps to reproduce

1. Take the Go key of an account whose billing page shows a paid subscription.
2. Run:

curl -sS -X POST https://opencode.ai/zen/go/v1/chat/completions \
  -H "Authorization: Bearer <your Go key>" -H "Content-Type: application/json" \
  -H "x-opencode-session: $(cat /proc/sys/kernel/random/uuid)" \
  -d '{"model":"glm-5.3-flash","messages":[{"role":"user","content":"ping"}],"max_tokens":5}'

3. Response is 403 An active OpenCode Go subscription is required to use Go models.
4. The same request without x-opencode-session returns a different error (400 MissingSessionID), so the request format itself is accepted.
5. The non-Go endpoint on the same key answers 403 Model access is disabled.

Screenshot and/or share link

No screenshot — the reproduction is text and is included above (curl transcript, 2026-09-30 12:39 MSK).

Operating System

Not OS-specific. Reproduced headless on Linux via curl; the same symptom is reported from Windows clients (#51049) and from the desktop app (#51689).

Terminal

curl, headless (no interactive terminal involved). The GUI client shows the same 403.