API usage primer for Claude changedclaude_api_primer
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4444 ```
4545</CodeGroup>
4646
47```text Output wrap
47```json Output
4848{
4949 "id": "msg_01XFDUDYJgAACzvnptvVoYEL",
5050 "type": "message",
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590590* `name`: The name of the tool being used
591591* `input`: An object containing the input being passed to the tool
592592
593```text wrap
593```json
594594{
595595 "role": "assistant",
596596 "content": [
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699699
700700#### Text delta
701701
702```text wrap
702```json
703703{
704704 "type": "content_block_delta",
705705 "index": 0,
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711711
712712For `tool_use` content blocks, deltas are *partial JSON strings*:
713713
714```text
714```json
715715{"type": "content_block_delta","index": 1,"delta": {"type": "input_json_delta","partial_json": "{\"location\": \"San Fra"}}}
716716```
717717
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719719
720720When using thinking with streaming:
721721
722```text wrap
722```json
723723{
724724 "type": "content_block_delta",
725725 "index": 0,
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732732
733733### Basic streaming request example
734734
735```text
735```sse
736736event: message_start
737737data: {"type": "message_start", "message": {"id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY", "type": "message", "role": "assistant", "content": [], "model": "claude-opus-5-5", "stop_reason": null, "stop_sequence": null, "usage": {"input_tokens": 25, "output_tokens": 1}}}
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