If a tool execution fails, what should the client return to Claude?

Question

Accepted Answer

A toolresult describing the error so Claude can recover or inform the user — Failed tools still need toolresult — tell Claude what broke so it can recover or explain.

Answer

Nothing; end the process without notice

Answer

A new system prompt containing the API key

Answer

An infinite loop of the same tooluse

If a tool execution fails, what should the client return to Claude?

Short Explanation and Infographic

Full Explanation