Tag: tool-calling

A step-by-step checklist for lifting a hand-rolled Anthropic tool-calling loop onto a standalone MCP server. The tool bodies move almost verbatim; what changes is where the schema comes from, how results are wrapped, and how errors cross the process boundary.

Use CodeAct (the agent writes executable code as its action) when your tasks chain many tools, loop, or move large data, and you can afford a sandbox. Use the JSON tool-calling loop for a handful of discrete, high-stakes actions where a code interpreter is overkill or unsafe. CodeAct wins on token cost and multi-step success rate; tool calling wins on safety and simplicity.

Use custom tool calling for one app you own end to end, MCP for any integration you want reused across Claude Code, Cursor, and ChatGPT, and OpenAPI plugins only as a bridge when you already have a spec. MCP is the cross-client standard in 2026; plugins are legacy.