google.internal.GmPart$stream
One `Part` of a content. Exactly one payload field is set; the rest are stripped before serialization.
Reference version
Signature
class google.internal.GmPart$streamOne Part of a content. Exactly one payload field is set; the rest are
stripped before serialization.
thoughtSignature is the exception: it is a SIBLING of the payload field,
not a payload of its own. Gemini 3 issues one with every functionCall it
emits and REQUIRES it back when that call is replayed in contents — a
bare replayed functionCall is rejected with HTTP 400 ("Function call is
missing a thought_signature in functionCall parts"), which breaks every
multi-turn tool loop on the 3.x models. See _gm_encode_call_id.
Source:<builtin>/google/ns_internal/gemini.bamlbytes 0–0
Fields
text
string | nullinlineData
fileData
functionCall
functionResponse
thoughtSignature
string | null