stream-json: result event `.result` drops all but the first text chunk when one assistant message streams as multiple events
In -p --output-format stream-json --verbose mode, when the model's final answer is emitted as multiple assistant events that share one message.id (one event per content block/chunk), the terminal result event's .result field contains only the first fragment of the answer text instead of the full concatenation.
Observed on claude-code 2.1.x with a JSON-schema-constrained prompt (--json-schema, --tools=): the model answered in plain text split across two assistant events (stop_reason: end_turn, complete and valid when the events' text blocks are concatenated), but .result carried only the first ~210 characters, truncated mid-JSON. Four occurrences across two days; a retry of the identical prompt that happened to stream as a single assistant event returned a complete .result.
Expected: .result equals the full final answer text (the concatenation of the final message's text blocks), regardless of how many stream events the message was chunked into.
Workaround we applied downstream: when .result is empty or unparseable, rebuild the answer by concatenating all assistant text blocks from the event stream in order.