--- title: "Changes to Create a Message Batch" method: POST path: "/v1/messages/batches" --- # Changes to Create a Message Batch `POST /v1/messages/batches` > Every recorded change to this endpoint, newest first. ## Timeline Changed in 23 of 68 revisions. - **2026-09-01** `d1d189d791d1` — 2 warning, 1 info - **2026-08-19** `67ee007cda1c` — 27 info - **2026-08-14** `e9d8152420c3` — 1 breaking, 1 info - **2026-08-13** `6e9020ec2b41` — 27 info - **2026-08-06** `538e9bd0db77` — 1 breaking - **2026-07-24** `a97790bd7f18` — 1 breaking, 1 info - **2026-06-30** `7caa9a75ddbc` — 1 info - **2026-06-29** `4465f98f96c1` — 1 info - **2026-06-24** `82c21eb736c8` — 1 info - **2026-06-18** `063bcb9d6cf9` — 1 breaking, 17 info - **2026-06-09** `00259327305f` — 1 breaking, 1 info - **2026-06-06** `546c704d347b` — 1 breaking, 2 info - **2026-05-28** `f9d488f9290d` — 5 info - **2026-05-06** `a4186730f56c` — 1 breaking - **2026-04-30** `6edc6519fd32` — 1 breaking, 1 info - **2026-04-16** `e0696f59ae07` — 1 breaking, 2 info - **2026-04-08** `69486316563e` — 1 breaking, 4 info - **2026-03-18** `dd2dcd00a757` — 1 info - **2026-03-16** `7fce94a3c9f7` — 1 breaking, 4 info - **2026-02-19** `29a6b7ba5194` — 1 info - **2026-02-18** `5387c517ad6a` — 15 info - **2026-02-17** `6924f88807cb` — 1 warning - **2026-02-17** `53a0f3638030` — 1 breaking, 36 info ## Changes - **2026-09-01** `d1d189d791d1` — 2 warning, 1 info - removed the request property `requests/items/params/tools/items/oneOf[subschema #7: BrowserToolset_20260801]/allowed_callers` - removed the request property `requests/items/params/tools/items/oneOf[subschema #9: ComputerToolset_20260801]/allowed_callers` - added `subschema #2, subschema #3` to the `requests/items/params/model` request property `anyOf` list - **2026-08-19** `67ee007cda1c` — 27 info - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/transformations` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/transformations` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/transformations` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #7: RequestToolUseBlock]/toolset_name` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/transformations` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/transformations` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/toolset_name` - added `#/components/schemas/ContainerParams` to the `requests/items/params/container` request property `anyOf` list - added `browser_state` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source` request property - added `file` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property - added `#/components/schemas/BrowserToolset_20260801, #/components/schemas/ComputerToolset_20260801` to the `requests/items/params/tools/items/` request property `oneOf` list - added `#/components/schemas/FileDocumentSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source` request property `oneOf` list - added `#/components/schemas/FileDocumentSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source` request property `oneOf` list - added `#/components/schemas/FileDocumentSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source` request property `oneOf` list - added `#/components/schemas/FileImageSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property `oneOf` list - added `#/components/schemas/FileImageSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/source` request property `oneOf` list - added `#/components/schemas/FileImageSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property `oneOf` list - added `#/components/schemas/FileImageSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #2: RequestImageBlock]/source` request property `oneOf` list - added `#/components/schemas/FileImageSource` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #2: RequestImageBlock]/source` request property `oneOf` list - added `#/components/schemas/RequestBrowserStateBlock` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/` request property `oneOf` list - **2026-08-14** `e9d8152420c3` — 1 breaking, 1 info - removed `#/components/schemas/RequestMidConvSystemBlock` from the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property `oneOf` list - removed `mid_conv_system` discriminator mapping keys from the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property - **2026-08-13** `6e9020ec2b41` — 27 info - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #2: RequestWebFetchResultBlock]/content/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #17: RequestMidConvSystemBlock]/content/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #17: RequestMidConvSystemBlock]/content/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #17: RequestMidConvSystemBlock]/content/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #3: RequestSearchResultBlock]/content/items/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/oneOf[subschema #4: RequestDocumentBlock]/source/oneOf[subschema #3: ContentBlockSource]/content/anyOf[subschema #2: content_block_source_content]/items/oneOf[subschema #1: RequestTextBlock]/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/system/anyOf[subschema #2]/items/citations/anyOf[subschema #1]/items/oneOf[subschema #1: RequestCharLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/system/anyOf[subschema #2]/items/citations/anyOf[subschema #1]/items/oneOf[subschema #2: RequestPageLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - the `requests/items/params/system/anyOf[subschema #2]/items/citations/anyOf[subschema #1]/items/oneOf[subschema #3: RequestContentBlockLocationCitation]/document_title/anyOf[subschema #1]/` request property's maxLength was increased from `255` to `500` - **2026-08-06** `538e9bd0db77` — 1 breaking - removed `subschema #17, subschema #18` from the `requests/items/params/model` request property `anyOf` list - **2026-07-24** `a97790bd7f18` — 1 breaking, 1 info - removed `subschema #5, subschema #6, subschema #8, subschema #12, subschema #13, subschema #16, subschema #17` from the `requests/items/params/model` request property `anyOf` list - added `subschema #5, subschema #6, subschema #7, subschema #9, subschema #13, subschema #14, subschema #17, subschema #18` to the `requests/items/params/model` request property `anyOf` list - **2026-06-30** `7caa9a75ddbc` — 1 info - added `subschema #2` to the `requests/items/params/model` request property `anyOf` list - **2026-06-29** `4465f98f96c1` — 1 info - added `#/components/schemas/WebSearchTool_20260318, #/components/schemas/WebFetchTool_20260318` to the `requests/items/params/tools/items/` request property `oneOf` list - **2026-06-24** `82c21eb736c8` — 1 info - added the new optional `header` request parameter `anthropic-user-profile-id` - **2026-06-18** `063bcb9d6cf9` — 1 breaking, 17 info - removed `subschema #17, subschema #18, subschema #19, subschema #20, subschema #21` from the `requests/items/params/model` request property `anyOf` list - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #10: WebSearchTool_20250305 -> subschema #11: WebSearchTool_20250305]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #11: WebFetchTool_20250910 -> subschema #12: WebFetchTool_20250910]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #12: WebSearchTool_20260209 -> subschema #13: WebSearchTool_20260209]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #13: WebFetchTool_20260209 -> subschema #14: WebFetchTool_20260209]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #14: WebFetchTool_20260309 -> subschema #15: WebFetchTool_20260309]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #15: ToolSearchToolBM25_20251119 -> subschema #16: ToolSearchToolBM25_20251119]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #16: ToolSearchToolRegex_20251119 -> subschema #17: ToolSearchToolRegex_20251119]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #1: Tool]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #2: BashTool_20250124]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #3: CodeExecutionTool_20250522]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #4: CodeExecutionTool_20250825]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #5: CodeExecutionTool_20260120]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #6: MemoryTool_20250818 -> subschema #7: MemoryTool_20250818]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #7: TextEditor_20250124 -> subschema #8: TextEditor_20250124]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #8: TextEditor_20250429 -> subschema #9: TextEditor_20250429]/allowed_callers/items/` - added the new `code_execution_20260521` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #9: TextEditor_20250728 -> subschema #10: TextEditor_20250728]/allowed_callers/items/` - added `#/components/schemas/CodeExecutionTool_20260521` to the `requests/items/params/tools/items/` request property `oneOf` list - **2026-06-09** `00259327305f` — 1 breaking, 1 info - removed `subschema #4` from the `requests/items/params/model` request property `anyOf` list - added `subschema #2, subschema #3, subschema #6` to the `requests/items/params/model` request property `anyOf` list - **2026-06-06** `546c704d347b` — 1 breaking, 2 info - removed `subschema #13, subschema #14` from the `requests/items/params/model` request property `anyOf` list - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #15: RequestToolSearchToolResultBlock]/content/anyOf[subschema #1: RequestToolSearchToolResultError]/error_message` - added `subschema #13, subschema #14` to the `requests/items/params/model` request property `anyOf` list - **2026-05-28** `f9d488f9290d` — 5 info - added `subschema #2` to the `requests/items/params/model` request property `anyOf` list - added `mid_conv_system` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property - added the new `system` enum value to the request property `requests/items/params/messages/items/role` - added the new `url_not_in_prior_context` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #11: RequestWebFetchToolResultBlock]/content/anyOf[subschema #1: RequestWebFetchToolResultError]/error_code` - added `#/components/schemas/RequestMidConvSystemBlock` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property `oneOf` list - **2026-05-06** `a4186730f56c` — 1 breaking - the `requests/items/params/tools/items/oneOf[subschema #9: TextEditor_20250728]/input_examples/items/additionalProperties/` request property type changed from `unknown` to no type - **2026-04-30** `6edc6519fd32` — 1 breaking, 1 info - the `requests/items/params/tools/items/oneOf[subschema #9: TextEditor_20250728]/input_examples/items/additionalProperties/` request property type changed from no type to `unknown` - the `requests/items/params/max_tokens` request property's min was decreased from `1.00` to `0.00` - **2026-04-16** `e0696f59ae07` — 1 breaking, 2 info - removed `subschema #13, subschema #14, subschema #15, subschema #16` from the `requests/items/params/model` request property `anyOf` list - added `subschema #2, subschema #14, subschema #15, subschema #16, subschema #17` to the `requests/items/params/model` request property `anyOf` list - added the new `xhigh` enum value to the request property `requests/items/params/output_config/effort/anyOf[subschema #1: EffortLevel]/` - **2026-04-08** `69486316563e` — 1 breaking, 4 info - removed `subschema #2` from the `requests/items/params/model` request property `anyOf` list - added `subschema #2, subschema #3` to the `requests/items/params/model` request property `anyOf` list - request property `requests/items/params/temperature` deprecated - request property `requests/items/params/top_k` deprecated - request property `requests/items/params/top_p` deprecated - **2026-03-18** `dd2dcd00a757` — 1 info - the `requests/items/params/metadata/user_id/anyOf[subschema #1]/` request property's maxLength was increased from `256` to `512` - **2026-03-16** `7fce94a3c9f7` — 1 breaking, 4 info - removed `subschema #3, subschema #6, subschema #7, subschema #8, subschema #9, subschema #10, subschema #11, subschema #14, subschema #15, subschema #16, subschema #17, subschema #18, subschema #19, subschema #20, subschema #21, subschema #22, subschema #23` from the `requests/items/params/model` request property `anyOf` list - added the new optional request property `requests/items/params/thinking/oneOf[subschema #1: ThinkingConfigEnabled]/display` - added the new optional request property `requests/items/params/thinking/oneOf[subschema #3: ThinkingConfigAdaptive]/display` - added `subschema #3, subschema #4, subschema #5, subschema #8, subschema #9, subschema #10, subschema #11, subschema #12, subschema #13, subschema #16` to the `requests/items/params/model` request property `anyOf` list - added `#/components/schemas/WebFetchTool_20260309` to the `requests/items/params/tools/items/` request property `oneOf` list - **2026-02-19** `29a6b7ba5194` — 1 info - added the new optional request property `requests/items/params/cache_control` - **2026-02-18** `5387c517ad6a` — 15 info - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #10: WebSearchTool_20250305]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #11: WebFetchTool_20250910]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #12: WebSearchTool_20260209]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #13: WebFetchTool_20260209]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #14: ToolSearchToolBM25_20251119]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #15: ToolSearchToolRegex_20251119]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #1: Tool]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #2: BashTool_20250124]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #3: CodeExecutionTool_20250522]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #4: CodeExecutionTool_20250825]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #5: CodeExecutionTool_20260120]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #6: MemoryTool_20250818]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #7: TextEditor_20250124]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #8: TextEditor_20250429]/allowed_callers/items/` - added the new `code_execution_20260120` enum value to the request property `requests/items/params/tools/items/oneOf[subschema #9: TextEditor_20250728]/allowed_callers/items/` - **2026-02-17** `6924f88807cb` — 1 warning - removed the request property `requests/items/params/speed` - **2026-02-17** `53a0f3638030` — 1 breaking, 36 info - request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` was restricted to a list of enum values - added the new optional request property `requests/items/params/container` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #10: RequestWebSearchToolResultBlock]/caller` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #7: RequestToolUseBlock]/caller` - added the new optional request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/caller` - added the new optional request property `requests/items/params/speed` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #1: Tool]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #1: Tool]/defer_loading` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #1: Tool]/input_examples` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #2: BashTool_20250124]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #2: BashTool_20250124]/defer_loading` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #2: BashTool_20250124]/input_examples` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #3: TextEditor_20250124 -> subschema #7: TextEditor_20250124]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #3: TextEditor_20250124 -> subschema #7: TextEditor_20250124]/defer_loading` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #3: TextEditor_20250124 -> subschema #7: TextEditor_20250124]/input_examples` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #4: TextEditor_20250429 -> subschema #8: TextEditor_20250429]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #4: TextEditor_20250429 -> subschema #8: TextEditor_20250429]/defer_loading` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #4: TextEditor_20250429 -> subschema #8: TextEditor_20250429]/input_examples` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #5: TextEditor_20250728 -> subschema #9: TextEditor_20250728]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #5: TextEditor_20250728 -> subschema #9: TextEditor_20250728]/defer_loading` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #5: TextEditor_20250728 -> subschema #9: TextEditor_20250728]/input_examples` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #6: WebSearchTool_20250305 -> subschema #10: WebSearchTool_20250305]/allowed_callers` - added the new optional request property `requests/items/params/tools/items/oneOf[subschema #6: WebSearchTool_20250305 -> subschema #10: WebSearchTool_20250305]/defer_loading` - added `subschema #3` to the `requests/items/params/model` request property `anyOf` list - the `name` request property const value `web_search` was removed - added `bash_code_execution_tool_result, code_execution_tool_result, container_upload, text_editor_code_execution_tool_result, tool_search_tool_result, web_fetch_tool_result` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property - added `tool_reference` discriminator mapping keys to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/` request property - added the new `bash_code_execution` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `code_execution` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `text_editor_code_execution` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `tool_search_tool_bm25` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `tool_search_tool_regex` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `web_fetch` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added the new `web_search` enum value to the request property `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #9: RequestServerToolUseBlock]/name` - added `#/components/schemas/CodeExecutionTool_20250522, #/components/schemas/CodeExecutionTool_20250825, #/components/schemas/CodeExecutionTool_20260120, #/components/schemas/MemoryTool_20250818, #/components/schemas/WebFetchTool_20250910, #/components/schemas/WebSearchTool_20260209, #/components/schemas/WebFetchTool_20260209, #/components/schemas/ToolSearchToolBM25_20251119, #/components/schemas/ToolSearchToolRegex_20251119` to the `requests/items/params/tools/items/` request property `oneOf` list - added `#/components/schemas/RequestToolReferenceBlock` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/oneOf[subschema #8: RequestToolResultBlock]/content/anyOf[subschema #2]/items/` request property `oneOf` list - added `#/components/schemas/RequestWebFetchToolResultBlock, #/components/schemas/RequestCodeExecutionToolResultBlock, #/components/schemas/RequestBashCodeExecutionToolResultBlock, #/components/schemas/RequestTextEditorCodeExecutionToolResultBlock, #/components/schemas/RequestToolSearchToolResultBlock, #/components/schemas/RequestContainerUploadBlock` to the `requests/items/params/messages/items/content/anyOf[subschema #2]/items/` request property `oneOf` list --- [Operation](https://skmtc.dev/anthropics/apis/anthropic-api/docs/v1/messages/batches/post.md) · [API](https://skmtc.dev/anthropics/apis/anthropic-api.md) · [Page](https://skmtc.dev/anthropics/apis/anthropic-api/changes/v1/messages/batches/post)