feat: add OpenAI Codex OAuth plugin (layer 1) #7
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Implements built-in OAuth authentication for ChatGPT Plus/Pro subscribers to use OpenAI models via their existing subscription. Features: - PKCE OAuth flow with OpenAI's auth endpoints - Local callback server on port 1455 - Cross-platform browser launching - Automatic token refresh - Integrated as default plugin in opencode Based on: https://github.com/numman-ali/opencode-openai-codex-auth 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add api.responses.read and api.responses.write scopes to OAuth config to fix "Missing scopes: api.responses.write" error when using OpenAI API. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Remove api.responses.read/write scopes as they are not permitted by the Codex OAuth client. API access is implicit with the token. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The OAuth token works with chatgpt.com/backend-api, not api.openai.com. - Change base URL to https://chatgpt.com/backend-api - Use /codex/responses endpoint - Add required headers: OpenAI-Beta, originator, chatgpt-account-id - Extract account ID from JWT token claims 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add custom fetch that rewrites /responses to /codex/responses. The SDK sends requests to standard paths but Codex backend expects the /codex prefix. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
…kend The Codex backend requires an 'instructions' field in the request body. Add request body transformation to include default instructions if not present. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
…r instructions - Add store:false (required by ChatGPT backend) - Extract system message from input array to use as instructions - Improve default instructions text 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The Codex backend expects instructions starting with the Codex identification string "You are Codex, based on GPT-5..." 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add stream=true (required by Codex backend) - Strip item IDs from input array (stateless operation) - Remove system message from input after extracting to instructions 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Embed the actual Codex system prompt from openai/codex repository. The backend validates instructions content. Source: https://github.com/openai/codex/blob/main/codex-rs/core/gpt_5_codex_prompt.md 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Delete instructions field entirely - backend validates strictly and uses model-specific defaults. Also remove system messages from input. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The external plugin has proper prompt alignment with the Codex backend. Use it as primary with built-in as fallback. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Use external opencode-openai-codex-auth plugin instead, which has proper prompt alignment with the Codex backend. The built-in version was added but never worked correctly. Changes: - Remove packages/openai-codex-auth/ directory - Remove fallback logic in plugin loader - Update dependencies 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Summary
Implements built-in OAuth authentication for ChatGPT Plus/Pro subscribers to use OpenAI models via their existing subscription.
Features
New Package
packages/openai-codex-auth/- Layer 1 built-in pluginUsage
opencode auth loginBased on: https://github.com/numman-ali/opencode-openai-codex-auth
Test plan
opencode auth loginshows the new option~/.opencode/data/auth.json🤖 Generated with Claude Code