sub2api-opencode-skill

Agent skill for configuring Sub2API as a provider in OpenCode.

What it does

Helps you correctly set up Sub2API's Antigravity proxy as an OpenCode provider, avoiding the common 404 pitfalls caused by SDK/endpoint mismatches.

Key insight: Sub2API's /antigravity endpoint uses Anthropic Messages API (/v1/messages) for Claude and Google Generative AI API (/v1beta/) for Gemini -- not OpenAI-compatible /v1/chat/completions.

Install

npx skills add likai/sub2api-opencode-skill

What's inside

• Correct SDK mapping for each model family
• Ready-to-use opencode.json templates (Claude-only, Gemini-only, Full setup)
• Step-by-step setup with connectivity verification
• Comprehensive troubleshooting for 404, 503, config errors
• Nginx reverse proxy notes
• Environment variable security best practices

Quick Config (Claude via Antigravity)

{
  "$schema": "https://opencode.ai/config.json",
  "model": "sub2api-claude/claude-sonnet-4-6",
  "provider": {
    "sub2api-claude": {
      "npm": "@ai-sdk/anthropic",
      "name": "Sub2API Claude",
      "options": {
        "baseURL": "https://your-sub2api-domain/antigravity/v1",
        "apiKey": "sk-your-api-key"
      },
      "models": {
        "claude-sonnet-4-6": {
          "name": "Claude Sonnet 4.6",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": {
            "input": ["text", "image", "pdf"],
            "output": ["text"]
          }
        }
      }
    }
  }
}

Common Mistakes

Mistake	Result	Fix
Using @ai-sdk/openai-compatible for Claude	404	Use @ai-sdk/anthropic
Using @ai-sdk/openai-compatible for Gemini	404	Use @ai-sdk/google-generative-ai
Using /v1 baseURL for Gemini	404	Use /v1beta
Missing modalities in model config	Images/PDF rejected	Add "input": ["text", "image", "pdf"]
provider as string instead of object	Config invalid	Use "provider": { ... }

References

• Sub2API - AI API Gateway (6K+ stars)
• OpenCode - Terminal AI coding assistant
• OpenCode Provider Docs

License

MIT