[Bug]: Missing API Key error with OpenCode Go provider (Kimi K2.5) while same API key works with OpenCode Zen #17541

Description

When attempting to use the OpenCode Go provider with the Kimi K2.5 model, the application displays a "Missing API Key" error. However, the exact same API key works correctly when switching to the OpenCode Zen provider.

I am uncertain whether OpenCode Go is expected to use the same API key as OpenCode Zen, or if a separate/different API key should be created. I need guidance on where to obtain the correct API key for the OpenCode Go provider.

Related Issues Reviewed

I have reviewed the following related issues and they do not address this specific scenario:

• Issue [Bug] "Provider returned error" consistently occurs with Kimi K2.5 via OpenCode Go on Windows #16685 - "Provider returned error" with Kimi K2.5 via OpenCode Go (different error message)
• Issue Kimi k2.5 shows "The API Key appears to be invalid or may have expired" with a working API key #14892 - "The API Key appears to be invalid" with Kimi K2.5 (different error message)
• Issue Opencode Go API #16480 - "Opencode Go API" (question about obtaining API key, but different context)

Steps to Reproduce

1. Open OpenCode CLI on Windows
2. Navigate to provider settings
3. Select OpenCode Go as the provider
4. Select Kimi K2.5 as the model
5. Use an API key created at https://opencode.ai/workspace/wrk_xxx/keys (same location where Zen API keys are created)
6. Attempt to send any prompt
7. Observe the "Missing API Key" error

Expected Behavior

Either:

• The OpenCode Go provider should accept the same valid OpenCode API key that works with the OpenCode Zen provider, OR
• Clear documentation/guidance on where to obtain the correct API key specifically for OpenCode Go

Actual Behavior

• Error message: "Missing API Key"
• Provider: OpenCode Go
• Model: Kimi K2.5
• The same API key works immediately when switching provider to OpenCode Zen
• Created multiple new API keys at https://opencode.ai/workspace/wrk_xxx/keys using the same process as for Zen - all fail with "Missing API Key"

Environment

• OpenCode Version: 1.2.26
• Client: OpenCode CLI
• Operating System: Windows
• Provider: OpenCode Go
• Model: Kimi K2.5
• API Key Source: https://opencode.ai/workspace/wrk_xxx/keys

Additional Context

• API keys are created through the OpenCode web interface at the URL above
• Same API key authentication method works for Zen but not for Go
• Unclear whether Go provider requires a different API key or different authentication method
• All attempts use freshly created API keys using identical workflow to Zen