GPT 5.6 Luna on OpenCode Go: [invalid_encrypted_content] upstream request fails with decryption error

Description

Bug Description

GPT 5.6 Luna model via OpenCode Go provider fails with an encrypted content
verification error. The upstream request cannot decrypt or parse the response.

Error Message

AI_APICallError: Error from provider (Console Go): Upstream request failed:
invalid_encrypted_content The encrypted content gAAA...kifQ could not be
verified. Reason: Encrypted content could not be decrypted or parsed.

Steps to Reproduce

1. Subscribe to OpenCode Go
2. Connect via /connect command
3. Select opencode-go/gpt-5.6-luna model
4. Send any prompt
5. Error occurs on response

Expected Behavior

Model should respond normally like other Go models (e.g., mimo-v2.5-pro works fine).

Environment

• OS: Windows 11
• OpenCode version: 1.18.21
• Provider: OpenCode Go
• Model: gpt-5.6-luna

Logs

timestamp=2026-08-20T16:27:21.387Z level=ERROR message="stream error"
providerID=opencode-go modelID=gpt-5.6-luna
error.error="AI_APICallError: Error from provider (Console Go):
Upstream request failed: invalid_encrypted_content..."

Additional Context

Other Go models (deepseek-v4-pro, mimo-v2.5-pro) work fine on same account.
Issue appears to be specific to GPT 5.6 Luna's encrypted content handling.

Plugins

No response

OpenCode version

No response

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

No file or test is identified in the report. First reproduce the failure with opencode-go/gpt-5.6-luna on OpenCode 1.18.21, then compare its response handling with the working deepseek-v4-pro or mimo-v2.5-pro models. Done means the Luna model response is decrypted and returned without invalid_encrypted_content.