Regression surfaced by the batch review: commit 8400128 switched
list_transcripts from unwrap_or_default to map_err(-32602). This
correctly errors on malformed payloads but also rejected the common
case where a client omits the 'arguments' field entirely — which
arrives as Value::Null, and serde_json::from_value does not
deserialise Null into a struct.
Short-circuits the Null case to Args::default() before attempting
deserialisation. Genuine shape mismatches ("limit": "twenty")
still return -32602 as the previous test asserts.
New regression test: tools/call with list_transcripts and no
arguments key must return a successful response.
Jake
a5bc45e847