Messages changedapi/messages
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### Thinking Config Between Tools
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10751075
10761076 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
10771077
1078 - `string`
1078 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
10791079
1080 - `"claude-fable-5-1" or "claude-opus-5-5" or "claude-mythos-5-1" or 15 more`
1081
10821080 The model that will complete your prompt.
10831081
10841082 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
10851083
1084 - `"claude-sonnet-5-5"`
1085
1086 Efficient model for coding and agents
1087
10861088 - `"claude-fable-5-1"`
10871089
10881090 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
from line 1099
10971099
10981100 - `"claude-sonnet-5"`
10991101
1100 High-performance model for coding and agents
1102 Efficient model for coding and agents
11011103
11021104 - `"claude-fable-5"`
11031105
from line 1159
11571159
11581160 New class of intelligence, strongest in coding and cybersecurity
11591161
1162 - `string`
1163
11601164- `cache_control: optional CacheControlEphemeral or null`
11611165
11621166 Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.
from line 1281
12771281
12781282- `stream: optional boolean`
12791283
1280 Whether to incrementally stream the response using server-sent events.
1284 Whether to incrementally stream the response using server-sent events. When `true`, SDKs return a raw event stream.
12811285
1282 See [streaming](https://platform.claude.com/docs/en/build-with-claude/streaming) for details.
1286 In the TypeScript, Python and Ruby SDKs, the recommended way to stream is `messages.stream()`. It sets `stream` for you and accumulates the events into the final message. See [Streaming with SDKs](https://platform.claude.com/docs/en/build-with-claude/streaming#streaming-with-sdks) for an example in each language.
12831287
12841288- `system: optional string or array of TextBlockParam`
12851289
from line 1341
13371341
13381342 - `type: "disabled"`
13391343
1344 - `ThinkingConfigBetweenTools object`
1345
1346 - `type: "between_tools"`
1347
13401348 - `ThinkingConfigAdaptive object`
13411349
13421350 - `type: "adaptive"`
from line 3922
39143922
39153923 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
39163924
3917 - `string`
3925 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
39183926
3919 - `"claude-fable-5-1" or "claude-opus-5-5" or "claude-mythos-5-1" or 15 more`
3920
39213927 The model that will complete your prompt.
39223928
39233929 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
39243930
3931 - `"claude-sonnet-5-5"`
3932
3933 Efficient model for coding and agents
3934
39253935 - `"claude-fable-5-1"`
39263936
39273937 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
from line 3946
39363946
39373947 - `"claude-sonnet-5"`
39383948
3939 High-performance model for coding and agents
3949 Efficient model for coding and agents
39403950
39413951 - `"claude-fable-5"`
39423952
from line 4006
39964006
39974007 New class of intelligence, strongest in coding and cybersecurity
39984008
4009 - `string`
4010
39994011 - `role: "assistant"`
40004012
40014013 Conversational role of the generated message.
from line 5570
55585570
55595571 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
55605572
5561 - `string`
5573 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
55625574
5563 - `"claude-fable-5-1" or "claude-opus-5-5" or "claude-mythos-5-1" or 15 more`
5564
55655575 The model that will complete your prompt.
55665576
55675577 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
55685578
5579 - `"claude-sonnet-5-5"`
5580
5581 Efficient model for coding and agents
5582
55695583 - `"claude-fable-5-1"`
55705584
55715585 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
from line 5594
55805594
55815595 - `"claude-sonnet-5"`
55825596
5583 High-performance model for coding and agents
5597 Efficient model for coding and agents
55845598
55855599 - `"claude-fable-5"`
55865600
from line 5654
56405654
56415655 New class of intelligence, strongest in coding and cybersecurity
56425656
5657 - `string`
5658
56435659- `cache_control: optional CacheControlEphemeral or null`
56445660
56455661 Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.
from line 5746
57305746
57315747 - `type: "disabled"`
57325748
5749 - `ThinkingConfigBetweenTools object`
5750
5751 - `type: "between_tools"`
5752
57335753 - `ThinkingConfigAdaptive object`
57345754
57355755 - `type: "adaptive"`
from line 8419
83998419
84008420 - `path: optional string or null`
84018421
8402 Where the executor saved the file, on the executor's filesystem. Only included when another tool in the same environment can read the file at that path.
8403
8404 maxLength: 4096, pattern: ^[^\x00-\x1f\x7f-\x9f\u2028\u2029]*$
8405
8406 - `size_bytes: optional number or null`
8407
8408 The completed download's size.
8409
8410 minimum: 0
8411
8412### Browser State Change Download Failed
8413
8414- `BrowserStateChangeDownloadFailed object`
8415
8416 A file download that failed — or was cancelled — during this call.
8417
8418 - `type: "download_failed"`
8419
8420 - `download_id: string`
8421
8422 The caller-assigned identifier for this download, stable across the state changes reporting it.
8423
8424 minLength: 1, maxLength: 4096, pattern: ^[^\x00-\x1f\x7f-\x
8422 Where the executor saved the file, on the executor's filesystem. Only included when a
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