event: message_start
data: {"type":"message_start","message":{"id":"msg_empty","model":"claude-opus-4-7","usage":{"input_tokens":9,"output_tokens":0,"cache_creation_input_tokens":0,"cache_read_input_tokens":0}}}

event: content_block_start
data: {"type":"content_block_start","index":0,"content_block":{"type":"tool_use","id":"toolu_EMPTY","name":"echo","input":{}}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"input_json_delta","partial_json":"{\"a\":\"1\""}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"input_json_delta","partial_json":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"input_json_delta","partial_json":",\"b\":2"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"input_json_delta","partial_json":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"input_json_delta","partial_json":"}"}}

event: content_block_stop
data: {"type":"content_block_stop","index":0}

event: message_delta
data: {"type":"message_delta","delta":{"stop_reason":"tool_use"},"usage":{"output_tokens":7}}

event: message_stop
data: {"type":"message_stop"}

