Are you running it locally or the hosted version? I say that because Anthropic models are really good about not lying that they executed a tool call but using another provider/model sometimes they lie to your face.

Does it produce an error or just lies to you?

I tried the web hosted one, and it just lied indeed.

I asked to replace a name, told me it was done and shows the, what should be result, but does not touch the document.