FastMCP validates tool arguments with a pydantic model whose extra-field
policy is 'ignore', so create_note(content=...) — a plausible near-miss
for body=, primed by add_task_log's content — ran successfully, stored
body: '', and left a record embedding/search cannot see. Two real notes
were persisted body-less before the pattern was noticed; create_task
only 'worked' because those calls happened to use the right name.
StrictArgsFastMCP rejects any tool call carrying arguments the tool does
not declare, before dispatch, with a did-you-mean hint when one is close
and the declared list when none is. Applied at the dispatch seam so
every tool gets the guarantee — an error the caller sees once beats data
half-written forever.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
