Create a Message changedapi/beta/messages/create
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from line 3102
31023102
31033103 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
31043104
3105 - `string`
3105 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
31063106
3107 - `"claude-fable-5-1" or "claude-opus-5-5" or "claude-mythos-5-1" or 15 more`
3108
31093107 The model that will complete your prompt.
31103108
31113109 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
31123110
3111 - `"claude-sonnet-5-5"`
3112
3113 Efficient model for coding and agents
3114
31133115 - `"claude-fable-5-1"`
31143116
31153117 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
from line 3126
31243126
31253127 - `"claude-sonnet-5"`
31263128
3127 High-performance model for coding and agents
3129 Efficient model for coding and agents
31283130
31293131 - `"claude-fable-5"`
31303132
from line 3186
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31853187 New class of intelligence, strongest in coding and cybersecurity
31863188
3189 - `string`
3190
31873191 - `name: "advisor"`
31883192
31893193 Name of the tool.
from line 3822
38183822
38193823 - `"fast"`
38203824
3821 - `thinking: optional BetaThinkingConfigEnabled or BetaThinkingConfigDisabled or BetaThinkingConfigAdaptive or null`
3825 - `thinking: optional BetaThinkingConfigEnabled or BetaThinkingConfigDisabled or BetaThinkingConfigBetweenTools or BetaThinkingConfigAdaptive or null`
38223826
38233827 - `BetaThinkingConfigEnabled object`
38243828
from line 3864
38603864
38613865 - `type: "disabled"`
38623866
3867 - `BetaThinkingConfigBetweenTools object`
3868
3869 - `type: "between_tools"`
3870
38633871 - `BetaThinkingConfigAdaptive object`
38643872
38653873 - `type: "adaptive"`
from line 3956
39483956
39493957- `stream: optional boolean`
39503958
3951 Whether to incrementally stream the response using server-sent events.
3959 Whether to incrementally stream the response using server-sent events. When `true`, SDKs return a raw event stream.
39523960
3953 See [streaming](https://platform.claude.com/docs/en/build-with-claude/streaming) for details.
3961 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.
39543962
39553963- `system: optional string or array of BetaTextBlockParam`
39563964
from line 3994
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39873995 - `BetaThinkingConfigDisabled object`
39883996
3997 - `BetaThinkingConfigBetweenTools object`
3998
39893999 - `BetaThinkingConfigAdaptive object`
39904000
39914001- `tool_choice: optional BetaToolChoice`
from line 6970
69606970
69616971 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
69626972
6963 - `string`
6973 - `"claude-sonnet-5-5" or "claude-fable-5-1" or "claude-opus-5-5" or 16 more`
69646974
6965 - `"claude-fable-5-1" or "claude-opus-5-5" or "claude-mythos-5-1" or 15 more`
6966
69676975 The model that will complete your prompt.
69686976
69696977 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
69706978
6979 - `"claude-sonnet-5-5"`
6980
6981 Efficient model for coding and agents
6982
69716983 - `"claude-fable-5-1"`
69726984
69736985 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
from line 6994
69826994
69836995 - `"claude-sonnet-5"`
69846996
6985 High-performance model for coding and agents
6997 Efficient model for coding and agents
69866998
69876999 - `"claude-fable-5"`
69887000
from line 7054
70427054
70437055 New class of intelligence, strongest in coding and cybersecurity
70447056
7057 - `string`
7058
70457059 - `name: "advisor"`
70467060
70477061 Name of the tool.
from line 7201
71877201
71887202 - `default_config: optional BetaMCPToolDefaultConfig`
71897203
7190 Default configuration applied to all tools from this server
7191
7192 - `defer_loading: optional boolean`
7193
7194 - `enabled: optional boolean`
7195
7196 - `tools: optional array of BetaMCPToolParam or null`
7197
7198 The server's tool listing, pinned: when present, the server is not asked for its tools before sampling and exactly these entries, with `default_config` and `configs` applied, are the toolset's tools. Copy it from the `mcp_tool_listing` block of an earlier response.
7199
7200 - `input_schema: map[unknown]`
7201
7202 The tool's input schema as the MCP server lists it, verbatim.
7203
7204 - `name: st
7204 Default configuration applied to all tools from this serve
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