Add Modal deployment with OpenRouter integration

[jakemannix]

Summary

Adds serverless deployment support for the MCP Gateway via Modal, along with OpenRouter integration for user-provided API keys instead of server-side credentials.

Features

Modal Deployment

• modal_app.py: Complete Modal deployment with separate gateway and UI images
• Gateway image includes Node.js for npx-based MCP servers
• Scaledown window (5min) and concurrent request support (max 100 inputs)
• Registry configuration via REGISTRY_FILE environment variable
• Fast, reproducible installs using uv

OpenRouter Integration

• Replaces server-side ANTHROPIC_API_KEY with user-provided OpenRouter key
• API key stored in browser localStorage (never persisted server-side)
• OpenAI-compatible API calls to OpenRouter
• Default model: anthropic/claude-3.5-haiku
• Privacy-focused: key only used for LLM calls, never logged

New Files

File	Purpose
modal_app.py	Modal deployment configuration with gateway and UI functions
demo/registries/modal-demo.json	Registry optimized for Modal (remote HTTP servers only)
.github/workflows/opencode.yml	OpenCode GitHub Actions integration

UI Enhancements

• API key input field with password masking
• localStorage persistence with automatic save/load
• HTMX request header injection for chat endpoint
• Link to openrouter.ai/keys for API key acquisition
• Privacy notice about client-side storage

Dependencies

• Add modal>=1.0.0 as optional dependency (modal extra)
• Install with: uv sync --extra modal

Deployment

# Install with Modal support
uv sync --extra modal

# Deploy to Modal
uv run modal deploy modal_app.py

# Configure gateway URL (after first deploy)
modal secret create gateway-config \
  GATEWAY_URL=https://YOUR-WORKSPACE--mcp-gateway-demo-gateway.modal.run

# Use full showcase (with subprocess servers)
REGISTRY_FILE=showcase.json uv run modal deploy modal_app.py

Testing

All existing tests pass (204 tests). Modal deployment tested with:

• Cloudflare Docs server (public, no auth)
• Cloudflare Radar server (OAuth-protected)
• Tool renaming and output projection features

🤖 Generated with Claude Code