Transport Bindings

ACT is a component contract, not a transport protocol. Transport adapters bridge external protocols to the ACT host.

MCP

The MCP adapter translates between the Model Context Protocol and ACT:

MCP	ACT
tools/list	list-tools(metadata)
tools/call	call-tool(tool-call)

# Start MCP stdio server
act mcp my-component.wasm

# Use with Claude Desktop, Cursor, etc.

Metadata is configured by the host (API keys, connection strings). The agent sends tool calls through standard MCP JSON-RPC.

HTTP (ACT-HTTP)

Pure REST endpoints — simpler than MCP’s JSON-RPC + SSE:

Endpoint	Method	Description
/tools	GET	List all tools
/call/{tool}	POST	Call a tool
/metadata-schema	GET	Get metadata JSON Schema

# Start HTTP server (default [::1]:3000)
act serve my-component.wasm --port 8080

# List tools
curl http://localhost:8080/tools

# Call a tool
curl -X POST http://localhost:8080/call/base64_encode \
  -H "Content-Type: application/json" \
  -d '{"arguments": {"input": "hello"}}'

ACT-HTTP is also a standard for non-WASM implementations. Any HTTP server implementing these endpoints is an ACT-HTTP component.

CLI

Direct command-line invocation:

# Call a specific tool
act call my-component.wasm tool-name \
  --args '{"key": "value"}' \
  --metadata '{"key": "value"}'

# List tools
act tools my-component.wasm

# Show component info
act info my-component.wasm