[bug] GPT-5.6 Luna/Terra return unsupported_country_region_territory via Zen from Hong Kong

[xxxxchaos]

Summary

OpenCode Zen rejects GPT-5.6 Luna and Terra requests from a Hong Kong server with unsupported_country_region_territory, while other models work with the same Zen API key and from the same host.

Could you confirm whether GPT-5.6 is intentionally unavailable from Hong Kong, or whether this is an upstream routing issue?

Endpoint

POST https://opencode.ai/zen/v1/responses

Results

Tested on 2026-08-02 around 08:50 UTC:

Model	Result
gpt-5.6-luna	HTTP 403
gpt-5.6-terra	HTTP 403
gpt-5.4-mini	HTTP 200
claude-haiku-4-5 via /messages	HTTP 200

Both IPv4 and IPv6 reproduce the GPT-5.6 failure.

Error

{
  "model": "gpt-5.6-luna",
  "error": {
    "param": null,
    "message": "Error from provider (Console): Upstream request failed: [unsupported_country_region_territory] Country, region, or territory not supported"
  }
}

gpt-5.6-terra returns the same error.

One reproduced request returned this non-sensitive Cloudflare trace header:

cf-ray: a24bd64b4ce4ba3a-SEA

Expected behavior

Since GPT-5.6 Luna and Terra are listed in the Zen model catalog, the request should either succeed or the documentation/model metadata should clearly indicate the applicable regional restriction.

Additional notes

• The Zen API key is valid.
• The request uses the documented Responses endpoint.
• No proxy is used on the server.
• No API key, server IP, or customer data is included in this report.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Zen: gpt-5.6-luna / gpt-5.6-terra fail with "Error from provider (Console): Upstream request failed" #39831: Same models (gpt-5.6-luna / gpt-5.6-terra) failing via Zen with "Upstream request failed" (HTTP 403) — very similar symptoms, possibly the same root cause
• OpenCode Zen lists GPT 5.6 Terra but cannot run it #38624: GPT-5.6 Terra listed in Zen model catalog but fails at runtime
• [bug] Country, region, or territory not supported error #8796: Same unsupported_country_region_territory error code via Zen (closed, may have context)

The regional detail (Hong Kong) is a useful differentiator, but the core failure mode overlaps significantly with #39831 in particular.

[muhammadshehzaib]

Hi! I would like to work on this issue. I've identified the root cause: the Zen proxy forwards the client's incoming Cloudflare geo/IP headers (like cf-connecting-ip, cf-ipcountry, etc.) directly to the upstream OpenAI endpoints. This causes OpenAI to geoblock requests when they originate from clients in Hong Kong.

I have a fix ready that strips these headers before forwarding the request, and I will open a Pull Request shortly