Appendix - MCP & A2A

What We Learned

• MCP standardizes tool/context integration; A2A connects agents that manage their own work.
• Understand protocol messages, transports, feature discovery and version compatibility.
• Expose narrow tools, readable resources and reusable prompts with validated contracts.
• Authorize calls with scoped credentials and audience checks; enforce permissions in code.
• Test servers and clients against injection, unsafe tool behavior and credential misuse.

Key Acronyms, Concepts & Jargon

Term	Short meaning
MCP	Model Context Protocol: standard interface for tools and context exposed to model applications.
A2A	Agent2Agent: protocol for communication and task exchange between agents.
Host / client / server	Application / its protocol connector / capability provider.
JSON-RPC	JavaScript Object Notation Remote Procedure Call: structured request/response message format.
stdio / HTTP	Standard input/output / Hypertext Transfer Protocol: local process / network transport.
Tool / resource / prompt	Callable operation / readable context / reusable message template.
Elicitation	A server requests additional user input through the client.
OAuth / PKCE	Authorization framework / Proof Key for Code Exchange: protects authorization-code flows.
Scope / token audience	Granted permissions / the service a token is intended for.
Confused deputy	A privileged service is tricked into acting for an unauthorized party.
Agent Card	Describes an A2A agent's capabilities and connection details.
Task / artifact	Tracked unit of agent work / output produced by that work.
Tool poisoning / SSRF	Malicious tool metadata / Server-Side Request Forgery targeting unintended services.
Protocol version	Agreed message rules; verify compatibility rather than assuming older features remain supported.

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