MCP vs. vendor tool formats
When the protocol pays for itself, and when it does not.
MCPOpenAI tool callsAnthropic tools
MCP is a portability bet. If you only use one vendor, the bet does not pay.
Use MCP when you anticipate multi-vendor deployments or want internal tools reusable across surfaces (IDE, chat, agent).
Stick with vendor format when you have one vendor and a small team.