Tagged Model Context Protocol · show all articles
Tool protocols standardize how a model asks a server to act. They say far less about what happens when a schema changes underfoot, a timeout fires before a write commits, a token expires mid-task, or a session drops — production finds every one of those gaps.
Four calling conventions, each dated to a real announcement: a manifest borrowed from web APIs, a schema built into the model call itself, incompatible framework wrappers, and a standard now governed by the vendors who once competed on incompatibility.
Inside a language model's context window, a tool description, a tool result and a resource all read the same as an instruction — which means a compromised or malicious MCP server can write the agent's next action itself.
A model that only emits text cannot query a database or send an email. Four documented patterns cross that boundary, and each one answers a different question — none is a smaller version of another.
A tool schema is a contract offered to a caller that cannot ask a follow-up question mid-call. This is a practitioner's guide to writing that contract so it survives retries, versioning, and a model that will eventually call it wrong.
A protocol is not an integration: what matters in a live session is which servers Claude Code will connect to, which of their tools it can run without asking, and what a caller can actually verify about a tool it did not write.
Crossing whether verification capacity keeps pace with code generation against whether permission and trust models converge on shared standards yields four falsifiable futures for Claude Code and agentic coding tools generally.
An agent can do exactly what its tool interfaces let it propose, no more. The schema, the granularity, the retry semantics and the error surface are not plumbing around the intelligence — they are the boundary of it.