What transport does MCP use?	JSON-RPC 2.0 over stdio (for local servers) or HTTP + Server-Sent Events (for remote servers).
What are the three MCP primitives?	Tools (callable functions), Resources (data readable by URI), and Prompts (server-defined context templates).
What is an A2A agent card?	A JSON document at a well-known URL declaring an agent's capabilities, input/output schemas, authentication requirements, and pricing — used for agent discovery.
What security gap exists in MCP's November 2024 specification?	No built-in authorization framework specifying which users can call which tools with which parameters. Authorization must be enforced at the application layer. OAuth 2.1 support was added in 2025 updates for remote servers.
When should you keep a raw OpenAPI spec alongside an MCP server?	When you also need to serve non-agent HTTP clients (browsers, Zapier, REST consumers) that will never speak MCP. Maintain both: OpenAPI for REST clients, MCP server wrapping the same functions for agent clients.
What is tool poisoning in the context of MCP?	A malicious MCP server returns tool descriptions designed to manipulate the LLM's behavior — hijacking its tool selection or injecting adversarial instructions through the tool description field.
What is the A2A task lifecycle?	Tasks transition through states: submitted (client sent the task), working (agent is executing), completed (result returned), failed (terminal error). Both parties track state.
Why is MCP adoption accelerating faster than bespoke OpenAPI wrappers?	Network effect: every major LLM client (Claude, OpenAI Agents SDK, Cursor, LangChain) now speaks MCP. One server implementation works with all clients; bespoke integrations require N×M maintenance.
Where in the system should interrupt semantics for humanoid home control be implemented — MCP server or orchestrator?	The orchestrator (LangGraph layer). The MCP server declares tools normally. The orchestrator intercepts calls to interrupt-listed tools (e.g., unlock-front-door) and requires human confirmation before executing.
What Python library is the canonical way to build an MCP server?	FastMCP, maintained by Anthropic — approximately 200 lines for a three-tool server, stdio and HTTP+SSE transport support.