bug: opencode auth login openai fails with 'fetch() URL is invalid' on Windows (v1.18.16) #41727

Description

opencode auth login openai fails immediately with Failed to load auth provider metadata from openai: fetch() URL is invalid. The browser OAuth flow never opens.

Environment

• OpenCode version: 1.18.16
• OS: Windows (PowerShell 7)
• Auth method: OpenAI OAuth (ChatGPT Plus)

Steps to reproduce

1. opencode auth logout openai (or start from a clean state)
2. opencode auth login openai
3. Observe immediate error — no browser window opens

Actual behavior

opencode auth login openai fails instantly:

Error: Failed to load auth provider metadata from openai: fetch() URL is invalid

The OpenAI provider IS listed as available in opencode auth list:

● OpenAI oauth

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