Model Router: Resilient Multi-Provider Subagent Engine

The Model Router equips Google Antigravity with multi-model dispatch, a quality-ranked cloud model directory, and zero-downtime rate-limit resilience, inspired by OpenCode's universal provider architecture and Austin Kleon's creative synthesis principles.

When working on demanding projects, hitting rate limits (HTTP 429 / quota exhaustion) on your primary model halts progress. This engine routes tasks to specialized cloud models and automatically cascades down a fallback chain if an upstream provider is throttled or offline.

Ranked Cloud Models Directory (Best on Top, Weakest at Bottom)

The router maintains an evaluated catalog across frontier cloud providers:

Configuration

The router reads from standard environment variables or a local configuration file at ~/.config/model-router/config.json.

export OPENROUTER_API_KEY="sk-or-..."  # Single key unlocks 200+ ranked models
export DEEPSEEK_API_KEY="sk-..."       # DeepSeek R1 & V3
export GROQ_API_KEY="gsk_..."          # Free tier available at console.groq.com
export DASHSCOPE_API_KEY="sk-..."      # Alibaba Qwen

Mounting in Antigravity as an MCP Server

Add to your Antigravity MCP configuration (~/.gemini/config/mcp_config.json):

{
  "mcpServers": {
    "model-router": {
      "command": "python3",
      "args": ["/home/hamza/Documents/skills/model-router/scripts/router.py", "--mcp"]
    }
  }
}

Antigravity tools exposed:

1. list_ranked_models: Inspects the directory of cloud models ranked from S-Tier to Deprecated.
2. cascade_query: Executes a prompt with automatic rate-limit failover across cloud providers.
3. consult_model: Explicitly queries a specific model (e.g. DeepSeek R1).
4. list_providers: Reports which providers are currently configured and online.

CLI Usage

# View ranked model directory
python3 scripts/router.py models

# Fetch live real-time directory from OpenRouter API
python3 scripts/router.py models --live

# Check provider readiness
python3 scripts/router.py status

# Run with automatic rate-limit failover
python3 scripts/router.py cascade --role reason --prompt "Solve this race condition in Node PTY"
python3 scripts/router.py cascade --role code --prompt "Write a TypeScript parser for JSON lines"