GET

/v1/schemas/anthropic/chat/v1/messages?beta=true

Accept:

kind inputactivity chathash 663f60e4…extracted Nov 11, 2026version currentsource upstream spec ↗

field	recorded source
schema	Source linked above. upstream-spec Source trace `690622377a5eedc0e9f2265ed755ee34dc0c52d35b47327f425777a550f45e1e` { "fetchedAt": 1794374425, "extractorVersion": "2", "verifiedAt": null }

Request body

24 properties · 3 required · 222 $defs

property	type	description	constraints
model*	string	The model that will complete your prompt.	22 known values
messages*	BetaInputMessageUnion[]	Input messages.
max_tokens*	integer	The maximum number of tokens to generate before stopping.	n ≥ 0
cache_control	BetaCacheControlEphemeral	Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.	nullable
compaction	BetaSummarizeCompaction	Compact the whole conversation and return a signed `compaction` block, alone, that a later request sends back first in `messages`, in place of the messages it summarizes. There is no trigger and no pause flag: sending the parameter compacts, and nothing is sam…	nullable
container	ContainerParams \| string	Container identifier for reuse across requests.	nullable
context_management	BetaContextManagementConfig	Context management configuration. This allows you to control how Claude manages context across multiple requests, such as whether to clear function results or not.	nullable
diagnostics	BetaDiagnosticsParam	Request-level diagnostics. Currently carries the previous response id for prompt-cache divergence reporting.	nullable
fallback_credit_token	string \| FallbackCreditTokenParam	The `fallback_credit_token` from a prior refusal's `stop_details`.	nullable
fallbacks	BetaFallbackConfigV2[] \| "default"	Opt-in server-side retry on one or more substitute models when the requested model declines for policy reasons. Tried in order: if the first entry also declines, the second is tried, and so on. Some models don't support fallbacks; on those models, a list of fa…	nullable
inference_geo	string	Specifies the geographic region for inference processing. If not specified, the workspace's `default_inference_geo` is used.	nullable
mcp_servers	BetaRequestMCPServerURLDefinition[]	MCP servers to be utilized in this request	items ≤ 20
metadata	BetaMetadata	An object describing metadata about the request.
output_config	BetaOutputConfig	Configuration options for the model's output, such as the output format.
output_format	BetaJsonOutputFormat	Deprecated: Use `output_config.format` instead. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs) A schema to specify Claude's output format in responses. This parameter will be removed in a future release.	nullable · deprecated
service_tier	enum	Determines whether to use priority capacity (if available) or standard capacity for this request.	auto \| standard_only
speed	enum	The inference speed mode for this request. `"fast"` enables high output-tokens-per-second inference. Some models require the `fast-mode-2026-02-01` beta header for any `speed` value. See [fast mode](https://platform.claude.com/docs/en/build-with-claude/fast-mode) for which models.	standard \| fast · nullable
stop_sequences	string[]	Custom text sequences that will cause the model to stop generating.
stream	boolean	Whether to incrementally stream the response using server-sent events. When `true`, SDKs return a raw event stream.
system	string \| BetaRequestTextBlock[]	System prompt.
thinking	ThinkingConfigEnabled \| ThinkingConfigDisabled \| ThinkingConfigBetweenTools \| …	Configuration for Claude's thinking.
thread	ThreadCreateParams \| ThreadContinueParams	Server-held conversation state (a Thread). `{"type": "create"}` asks the server to hold this conversation's state under the response's `id`; `{"type": "continue", "previous_message_id": ...}` resumes from a previous response so only the new turn's messages are sent. The response shape is unchanged.	nullable
tool_choice	ToolChoiceAuto \| ToolChoiceAny \| ToolChoiceTool \| …	How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.
tools	BetaToolUnion[]	Definitions of tools that the model may use.

Types

222 $defs

BetaAdvisorTool_20260301object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caching	BetaCacheControlEphemeral	Caching for the advisor's own prompt. When set, each advisor call writes a cache entry at the given TTL so subsequent calls in the same conversation read the stable prefix. When omitted, the advisor prompt is not cached.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_tokens	integer	Bounds the advisor's total output (thinking + text) per call. When the advisor hits this cap, the returned advisor_result or advisor_redacted_result block carries stop_reason='max_tokens', and a truncation note is appended to the advice text the worker model sees (inside the encrypted blob in redacted mode). When set, the API also passes the advisor its remaining-token budget, so the advisor shapes its output toward the cap. When omitted, the advisor model's default output cap applies and the API doesn't pass a budget.	n ≥ 1024 · nullable
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
model*	string	The model that will complete your prompt.	22 known values
name*	const	Name of the tool.	"advisor"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"advisor_20260301"

BetaAdvisorToolResultErrorCodeenum

BetaAllowedCallerenum

Specifies who can invoke a tool.

direct | code_execution_20250825 | code_execution_20260120 | code_execution_20260521

BetaAssistantInputMessageobject

content*	string \| BetaInputContentBlock[]
role*	const		"assistant"

BetaBase64ImageSourceobject

data*	string	format: byte
media_type*	enum	image/jpeg \| image/png \| image/gif \| image/webp
type*	const	"base64"

BetaBase64PDFSourceobject

data*	string	format: byte
media_type*	const	"application/pdf"
type*	const	"base64"

BetaBashCodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded | output_file_too_large

BetaBashTool_20241022object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"bash"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"bash_20241022"

BetaBashTool_20250124object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"bash"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"bash_20250124"

BetaBrowserCloseTabConfigobject

``close_tab``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserDoubleClickConfigobject

``double_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserFileUploadConfigobject

``file_upload``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserFindConfigobject

``find``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserFormInputConfigobject

``form_input``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserGetPageTextConfigobject

``get_page_text``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserHoldKeyConfigobject

``hold_key``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserHoverConfigobject

``hover``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserJavascriptExecConfigobject

``javascript_exec``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserKeyConfigobject

``key``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserLeftClickConfigobject

``left_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserLeftClickDragConfigobject

``left_click_drag``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserLeftMouseDownConfigobject

``left_mouse_down``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserLeftMouseUpConfigobject

``left_mouse_up``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserListTabsConfigobject

``list_tabs``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserMiddleClickConfigobject

``middle_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserMouseMoveConfigobject

``mouse_move``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserNavigateConfigobject

``navigate``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserNewTabConfigobject

``new_tab``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserReadConsoleConfigobject

``read_console``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserReadNetworkConfigobject

``read_network``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserReadPageConfigobject

``read_page``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserRightClickConfigobject

``right_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserScreenshotConfigobject

``screenshot``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserScrollConfigobject

``scroll``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserScrollToConfigobject

``scroll_to``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserStateChangeDownloadCompletedobject

A file download that finished during this call, reported with the same `download_id` as its `download_started` — or without a prior `download_started`, when the download finished during the call that started it (at most one state change per `download_id` per r…

download_id*	string	The caller-assigned identifier for this download, stable across the state changes reporting it.	length ≥ 1 · length ≤ 4096
path	string	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.	length ≤ 4096 · nullable
size_bytes	integer	The completed download's size.	n ≥ 0 · nullable
type*	const		"download_completed"
url*	string	The final post-redirect URL the download was served from.	length ≤ 4096

BetaBrowserStateChangeDownloadFailedobject

A file download that failed — or was cancelled — during this call.

download_id*	string	The caller-assigned identifier for this download, stable across the state changes reporting it.	length ≥ 1 · length ≤ 4096
error	string	The failure or cancellation detail, when known.	length ≤ 4096 · nullable
type*	const		"download_failed"
url*	string	The final post-redirect URL the download was served from.	length ≤ 4096

BetaBrowserStateChangeDownloadStartedobject

A file download that started during this call.

download_id*	string	The caller-assigned identifier for this download, stable across the state changes reporting it.	length ≥ 1 · length ≤ 4096
type*	const		"download_started"
url*	string	The final post-redirect URL the download was served from.	length ≤ 4096

BetaBrowserStateChangeTabOpenedobject

A tab this call's execution opened that remains open at its end — the creation delta of the `tabs` inventory, not an event log.

tab_id*	string	The `tab_id` of the opened tab, present in `tabs`.	length ≥ 1 · length ≤ 4096
type*	const		"tab_opened"

BetaBrowserStateTabEntryobject

One open browser tab reported in a `browser_state` block's `tabs` inventory.

active	boolean	Whether this tab is the active tab after this call. Whenever `tabs` is non-empty, exactly one entry is marked `active: true`.
tab_id*	string	The caller-assigned identifier for this tab, unique within the inventory.	length ≥ 1 · length ≤ 4096
title*	string	The title of the page the tab is showing. May be empty.	length ≤ 4096
url*	string	The URL of the page the tab is showing. May be empty.	length ≤ 4096

BetaBrowserSwitchTabConfigobject

``switch_tab``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserToolset_20260801object

The browser toolset: a single ``tools[]`` entry (carrying no ``name``) that declares the browser tool family. The model is served the family's tool with any members disabled via ``configs`` removed from its schema.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
configs	BetaBrowserToolsetConfigs	Per-member configuration for ``browser_toolset_20260801``: one optional field per member tool, keyed by the member name — the same name the member's ``tool_use`` blocks carry. Every member is an accepted key, and a member's defaults apply wherever its key is a…	nullable
type*	const		"browser_toolset_20260801"

BetaBrowserToolsetConfigsobject

Per-member configuration for ``browser_toolset_20260801``: one optional field per member tool, keyed by the member name — the same name the member's ``tool_use`` blocks carry. Every member is an accepted key, and a member's defaults apply wherever its key is a…

close_tab	BetaBrowserCloseTabConfig	``close_tab``'s config overrides.	nullable
double_click	BetaBrowserDoubleClickConfig	``double_click``'s config overrides.	nullable
file_upload	BetaBrowserFileUploadConfig	``file_upload``'s config overrides.	nullable
find	BetaBrowserFindConfig	``find``'s config overrides.	nullable
form_input	BetaBrowserFormInputConfig	``form_input``'s config overrides.	nullable
get_page_text	BetaBrowserGetPageTextConfig	``get_page_text``'s config overrides.	nullable
hold_key	BetaBrowserHoldKeyConfig	``hold_key``'s config overrides.	nullable
hover	BetaBrowserHoverConfig	``hover``'s config overrides.	nullable
javascript_exec	BetaBrowserJavascriptExecConfig	``javascript_exec``'s config overrides.	nullable
key	BetaBrowserKeyConfig	``key``'s config overrides.	nullable
left_click	BetaBrowserLeftClickConfig	``left_click``'s config overrides.	nullable
left_click_drag	BetaBrowserLeftClickDragConfig	``left_click_drag``'s config overrides.	nullable
left_mouse_down	BetaBrowserLeftMouseDownConfig	``left_mouse_down``'s config overrides.	nullable
left_mouse_up	BetaBrowserLeftMouseUpConfig	``left_mouse_up``'s config overrides.	nullable
list_tabs	BetaBrowserListTabsConfig	``list_tabs``'s config overrides.	nullable
middle_click	BetaBrowserMiddleClickConfig	``middle_click``'s config overrides.	nullable
mouse_move	BetaBrowserMouseMoveConfig	``mouse_move``'s config overrides.	nullable
navigate	BetaBrowserNavigateConfig	``navigate``'s config overrides.	nullable
new_tab	BetaBrowserNewTabConfig	``new_tab``'s config overrides.	nullable
read_console	BetaBrowserReadConsoleConfig	``read_console``'s config overrides.	nullable
read_network	BetaBrowserReadNetworkConfig	``read_network``'s config overrides.	nullable
read_page	BetaBrowserReadPageConfig	``read_page``'s config overrides.	nullable
right_click	BetaBrowserRightClickConfig	``right_click``'s config overrides.	nullable
screenshot	BetaBrowserScreenshotConfig	``screenshot``'s config overrides.	nullable
scroll	BetaBrowserScrollConfig	``scroll``'s config overrides.	nullable
scroll_to	BetaBrowserScrollToConfig	``scroll_to``'s config overrides.	nullable
switch_tab	BetaBrowserSwitchTabConfig	``switch_tab``'s config overrides.	nullable
triple_click	BetaBrowserTripleClickConfig	``triple_click``'s config overrides.	nullable
type	BetaBrowserTypeConfig	``type``'s config overrides.	nullable
wait	BetaBrowserWaitConfig	``wait``'s config overrides.	nullable
zoom	BetaBrowserZoomConfig	``zoom``'s config overrides.	nullable

BetaBrowserTripleClickConfigobject

``triple_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserTypeConfigobject

``type``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserWaitConfigobject

``wait``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaBrowserZoomConfigobject

``zoom``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaCacheControlEphemeralobject

ttl	enum	The time-to-live for the cache control breakpoint.	5m \| 1h
type*	const		"ephemeral"

BetaClearThinking20251015object

keep	BetaThinkingTurns \| BetaAllThinkingTurns \| "all"	Number of most recent assistant turns to keep thinking blocks for. Older turns will have their thinking blocks removed.
type*	const		"clear_thinking_20251015"

BetaClearToolUses20250919object

clear_at_least	BetaInputTokensClearAtLeast	Minimum number of tokens that must be cleared when triggered. Context will only be modified if at least this many tokens can be removed.	nullable
clear_tool_inputs	boolean \| string[]	Whether to clear all tool inputs (bool) or specific tool inputs to clear (list)	nullable
exclude_tools	string[]	Tool names whose uses are preserved from clearing	nullable
keep	BetaToolUsesKeep	Number of tool uses to retain in the conversation
trigger	InputTokensTrigger \| ToolUsesTrigger	Condition that triggers the context management strategy
type*	const		"clear_tool_uses_20250919"

BetaCodeExecutionTool_20250522object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"code_execution"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"code_execution_20250522"

BetaCodeExecutionTool_20250825object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"code_execution"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"code_execution_20250825"

BetaCodeExecutionTool_20260120object

A `tools` entry for the code execution tool, version `code_execution_20260120`. It adds REPL state persistence to version `code_execution_20250825`.

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"code_execution"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"code_execution_20260120"

BetaCodeExecutionTool_20260521object

Code execution tool with REPL state persistence.

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"code_execution"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"code_execution_20260521"

BetaCodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded

BetaCompact20260112object

Automatically compact older context when reaching the configured trigger threshold.

instructions	string	Additional instructions for summarization.	nullable
pause_after_compaction	boolean	Whether to pause after compaction and return the compaction block to the user.
trigger	BetaInputTokensTrigger	When to trigger compaction. Defaults to 150000 input tokens.	nullable
type*	const		"compact_20260112"

BetaCompactionConfigBetaSummarizeCompaction

Compact the whole conversation and return a signed `compaction` block, alone, that a later request sends back first in `messages`, in place of the messages it summarizes. There is no trigger and no pause flag: sending the parameter compacts, and nothing is sam…

instructions	string	Replaces the server's default summarization prompt for this request. An empty or whitespace-only value counts as absent.	length ≤ 16384 · nullable
type*	const		"summarize"

BetaComputerCursorPositionConfigobject

``cursor_position``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerDoubleClickConfigobject

``double_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerHoldKeyConfigobject

``hold_key``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerKeyConfigobject

``key``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerLeftClickConfigobject

``left_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerLeftClickDragConfigobject

``left_click_drag``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerLeftMouseDownConfigobject

``left_mouse_down``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerLeftMouseUpConfigobject

``left_mouse_up``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerMiddleClickConfigobject

``middle_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerMouseMoveConfigobject

``mouse_move``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerRightClickConfigobject

``right_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerScreenshotConfigobject

``screenshot``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerScrollConfigobject

``scroll``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerToolset_20260801object

The computer toolset: a single ``tools[]`` entry (carrying no ``name``) that declares the computer tool family. The model is served the family's tool with any members disabled via ``configs`` removed from its schema. Every member is enabled by default, zoom in…

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
configs	BetaComputerToolsetConfigs	Per-member configuration for ``computer_toolset_20260801``: one optional field per member tool, keyed by the member name — the same name the member's ``tool_use`` blocks carry. Every member is an accepted key, and a member's defaults apply wherever its key is …	nullable
type*	const		"computer_toolset_20260801"

BetaComputerToolsetConfigsobject

Per-member configuration for ``computer_toolset_20260801``: one optional field per member tool, keyed by the member name — the same name the member's ``tool_use`` blocks carry. Every member is an accepted key, and a member's defaults apply wherever its key is …

cursor_position	BetaComputerCursorPositionConfig	``cursor_position``'s config overrides.	nullable
double_click	BetaComputerDoubleClickConfig	``double_click``'s config overrides.	nullable
hold_key	BetaComputerHoldKeyConfig	``hold_key``'s config overrides.	nullable
key	BetaComputerKeyConfig	``key``'s config overrides.	nullable
left_click	BetaComputerLeftClickConfig	``left_click``'s config overrides.	nullable
left_click_drag	BetaComputerLeftClickDragConfig	``left_click_drag``'s config overrides.	nullable
left_mouse_down	BetaComputerLeftMouseDownConfig	``left_mouse_down``'s config overrides.	nullable
left_mouse_up	BetaComputerLeftMouseUpConfig	``left_mouse_up``'s config overrides.	nullable
middle_click	BetaComputerMiddleClickConfig	``middle_click``'s config overrides.	nullable
mouse_move	BetaComputerMouseMoveConfig	``mouse_move``'s config overrides.	nullable
right_click	BetaComputerRightClickConfig	``right_click``'s config overrides.	nullable
screenshot	BetaComputerScreenshotConfig	``screenshot``'s config overrides.	nullable
scroll	BetaComputerScrollConfig	``scroll``'s config overrides.	nullable
triple_click	BetaComputerTripleClickConfig	``triple_click``'s config overrides.	nullable
type	BetaComputerTypeConfig	``type``'s config overrides.	nullable
wait	BetaComputerWaitConfig	``wait``'s config overrides.	nullable
zoom	BetaComputerZoomConfig	``zoom``'s config overrides.	nullable

BetaComputerTripleClickConfigobject

``triple_click``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerTypeConfigobject

``type``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerUseTool_20241022object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
display_height_px*	integer	The height of the display in pixels.	n ≥ 1
display_number	integer	The X11 display number (e.g. 0, 1) for the display.	n ≥ 0 · nullable
display_width_px*	integer	The width of the display in pixels.	n ≥ 1
input_examples	object[]
name*	const	Name of the tool.	"computer"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"computer_20241022"

BetaComputerUseTool_20250124object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
display_height_px*	integer	The height of the display in pixels.	n ≥ 1
display_number	integer	The X11 display number (e.g. 0, 1) for the display.	n ≥ 0 · nullable
display_width_px*	integer	The width of the display in pixels.	n ≥ 1
input_examples	object[]
name*	const	Name of the tool.	"computer"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"computer_20250124"

BetaComputerUseTool_20251124object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
display_height_px*	integer	The height of the display in pixels.	n ≥ 1
display_number	integer	The X11 display number (e.g. 0, 1) for the display.	n ≥ 0 · nullable
display_width_px*	integer	The width of the display in pixels.	n ≥ 1
enable_zoom	boolean	Whether to enable an action to take a zoomed-in screenshot of the screen.
input_examples	object[]
name*	const	Name of the tool.	"computer"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"computer_20251124"

BetaComputerWaitConfigobject

``wait``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaComputerZoomConfigobject

``zoom``'s config overrides.

defer_loading	boolean	Defer loading for this member. Must resolve to the same value on every enabled member of the toolset.	nullable
enabled	boolean	Whether this member is offered to the model. Default is per member, per the toolset's documentation. A member whose enabled resolves false is withheld from the served schema.	nullable

BetaContainerParamsobject

Container parameters with skills to be loaded.

id	string	Container id	nullable
skills	BetaSkillParams[]	List of skills to load in the container	items ≤ 20 · nullable

BetaContentBlockSourceobject

content*	string \| BetaRequestTextBlock \| BetaRequestImageBlock[]
type*	const		"content"

BetaContextManagementConfigobject

edits

BetaClearToolUses20250919 | BetaClearThinking20251015 | BetaCompact20260112[]

List of context management edits to apply

items ≥ 0

BetaDiagnosticsParamobject

Request-level diagnostics. Currently carries the previous response id for prompt-cache divergence reporting.

previous_message_id

string

The `id` (`msg_...`) from this client's previous /v1/messages response. The server compares that request's prompt fingerprint against this one and returns `diagnostics.cache_miss_reason` when the prompt-cache prefix could not be reused. Pass `null` on the first turn to opt in without a prior message to compare.

length ≤ 256 · nullable

BetaDirectCallerobject

Tool invocation directly from the model.

type*

const

"direct"

BetaEffortLevelenum

All possible effort levels.

low | medium | high | xhigh | max

BetaFallbackConfigV2object

One entry in the `fallbacks` chain on a `/v1/messages` request.

max_tokens	integer	The `max_tokens` for the fallback attempt that uses this `fallbacks` entry's `model`, in place of the request's `max_tokens`. If you leave it out or set it to `null`, the attempt uses the request's `max_tokens`. See the [refusals and fallback guide](https://platform.claude.com/docs/en/build-with-claude/refusals-and-fallback#naming-your-own-fallback-models) to learn more about fallback entries.	nullable
model*	string	The model that will complete your prompt.	22 known values
output_config	BetaOutputConfig	Output parameters for the fallback attempt that uses this `fallbacks` entry's `model`, combined with the request's `output_config` one field at a time. - `format`: If you leave it out, the attempt uses the request's `format`. If you set it to `null`, the attempt runs without a format. - `effort`: If you leave it out, the attempt uses the request's `effort` when `model` supports that level with the attempt's `thinking`. If the request doesn't set `effort`, if `model` doesn't support the level, or if you set `effort` to `null`, the attempt runs at the default effort of `model`. - `task_budget`: If you leave it out, the attempt uses the request's `task_budget` when `model` accepts a task budget of that size. If the request doesn't set `task_budget`, if `model` doesn't accept it, or if you set `task_budget` to `null`, the attempt runs without a task budget. Set `output_config` to `null` to run the attempt without a format or a task budget, at the default effort of `model`. These rules apply with the `server-side-fallback-2026-07-01` beta header.	nullable
speed	enum	The inference speed mode for the fallback attempt that uses this `fallbacks` entry's `model`. If you leave it out, the attempt runs at `fast` speed only when the request sets `speed` to `fast` and your organization can use fast mode on `model`. Otherwise, or when you set this field to `null`, the attempt runs at `standard` speed. These rules apply with the `server-side-fallback-2026-07-01` beta header.	standard \| fast · nullable
thinking	ThinkingConfigEnabled \| ThinkingConfigDisabled \| ThinkingConfigBetweenTools \| …	The thinking configuration for the fallback attempt that uses this `fallbacks` entry's `model`. If you leave it out, the attempt uses the request's `thinking` when `model` supports that thinking `type`. If you leave it out and the request's thinking `type` is `between_tools` but `model` doesn't support `between_tools`, the attempt uses `disabled` if `model` supports it. Otherwise, if `model` doesn't support the request's thinking `type`, if the request doesn't set `thinking`, or if you set this field to `null`, the attempt uses the thinking `type` that `model` uses when a request leaves out `thinking`. The request's `thinking.display` still applies where `model` allows it. These rules apply with the `server-side-fallback-2026-07-01` beta header.	nullable

BetaFallbackCreditTokenParamobject

Object form of ``fallback_credit_token``: the token plus a redemption mode.

mode	enum	How a failing token affects the retry. `strict` (the default, and the bare-string behavior): a failing redemption is a 400 and the retry is not served. `best_effort`: the retry is served either way — a token-layer failure no longer rejects the request; the ret…	strict \| best_effort
token*	string	The opaque `fallback_credit_token` from a prior refusal's `stop_details` — the same string the bare-string form carries.	length ≥ 1 · length ≤ 2048

BetaFileDocumentSourceobject

file_id*	string
type*	const		"file"

BetaFileImageSourceobject

file_id*	string
type*	const		"file"

BetaInputContentBlockRequestTextBlock | RequestImageBlock | RequestDocumentBlock | …

BetaInputMessageContentstring | BetaInputContentBlock[]

BetaInputMessageUnionUserInputMessage | AssistantInputMessage | SystemInputMessage

BetaInputSchemaobject

properties	object	nullable
required	string[]	nullable
type*	const	"object"

BetaInputTokensClearAtLeastobject

type*	const		"input_tokens"
value*	integer		n ≥ 0

BetaInputTokensTriggerobject

type*	const		"input_tokens"
value*	integer		n ≥ 1

BetaJsonOutputFormatobject

schema*	object	The JSON schema of the format
type*	const		"json_schema"

BetaJsonValueany

BetaMCPToolobject

A tool as an MCP server lists it: its name on that server, its description, and its input schema.

description	string	The tool's description as the MCP server lists it.	nullable
input_schema*	object	The tool's input schema as the MCP server lists it, verbatim.
name*	string	The tool's name as the MCP server lists it (not prefixed with the server name).	length ≥ 1

BetaMCPToolConfigobject

Configuration for a specific tool in an MCP toolset.

defer_loading	boolean
enabled	boolean

BetaMCPToolDefaultConfigobject

Default configuration for tools in an MCP toolset.

defer_loading	boolean
enabled	boolean

BetaMCPToolsetobject

Configuration for a group of tools from an MCP server.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
configs	object	Configuration overrides for specific tools, keyed by tool name	nullable
default_config	BetaMCPToolDefaultConfig	Default configuration applied to all tools from this server
mcp_server_name*	string	Name of the MCP server to configure tools for	length ≥ 1 · length ≤ 255
tools	BetaMCPTool[]	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.	nullable
type*	const		"mcp_toolset"

BetaMemoryTool_20250818object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"memory"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"memory_20250818"

BetaMetadataobject

user_id

string

An external identifier for the user who is associated with the request. This should be a uuid, hash value, or other opaque identifier. Anthropic may use this id to help detect abuse. Do not include any identifying information such as name, email address, or phone number.

length ≤ 512 · nullable

BetaOutputConfigobject

effort	enum	All possible effort levels.	low \| medium \| high \| xhigh \| max · nullable
format	BetaJsonOutputFormat	A schema to specify Claude's output format in responses. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs)	nullable
task_budget	BetaTokenTaskBudget	User-configurable total token budget across contexts.	nullable

BetaPlainTextSourceobject

data*	string
media_type*	const	"text/plain"
type*	const	"text"

BetaRequestAdvisorRedactedResultBlockobject

encrypted_content*	string	Opaque blob produced by a prior response; must be round-tripped verbatim.
stop_reason	string		nullable
type*	const		"advisor_redacted_result"

BetaRequestAdvisorResultBlockobject

stop_reason	string	nullable
text*	string
type*	const	"advisor_result"

BetaRequestAdvisorToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	RequestAdvisorToolResultError \| RequestAdvisorResultBlock \| RequestAdvisorRedactedResultBlock
tool_use_id*	string
type*	const		"advisor_tool_result"

BetaRequestAdvisorToolResultErrorobject

error_code*	enum		max_uses_exceeded \| prompt_too_long \| too_many_requests \| overloaded \| unavailable \| execution_time_exceeded · +1 more
type*	const		"advisor_tool_result_error"

BetaRequestBashCodeExecutionOutputBlockobject

file_id*	string
type*	const		"bash_code_execution_output"

BetaRequestBashCodeExecutionResultBlockobject

content*	BetaRequestBashCodeExecutionOutputBlock[]
return_code*	integer
stderr*	string
stdout*	string
type*	const	"bash_code_execution_result"

BetaRequestBashCodeExecutionToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	RequestBashCodeExecutionToolResultError \| RequestBashCodeExecutionResultBlock
tool_use_id*	string
type*	const		"bash_code_execution_tool_result…

BetaRequestBashCodeExecutionToolResultErrorobject

error_code*	enum		invalid_tool_input \| unavailable \| too_many_requests \| execution_time_exceeded \| output_file_too_large
type*	const		"bash_code_execution_tool_result…

BetaRequestBrowserStateBlockobject

The caller's browser state after a browser toolset member call — the full inventory of open tabs, which tab is active, and any side effects (tabs opened, download state changes) the call produced.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
state_changes	BetaBrowserStateChangeTabOpened \| BetaBrowserStateChangeDownloadStarted \| BetaBrowserStateChangeDownloadCompleted[]	Tabs opened and download state changes during this call. "Nothing to report" is expressed by omitting the field, never by an empty list.	items ≥ 1 · items ≤ 200 · nullable
tabs*	BetaBrowserStateTabEntry[]	All tabs open in the browser after this call — the full inventory, not a delta. May be empty. Whenever non-empty, exactly one entry carries `active: true`.	items ≤ 100
type*	const		"browser_state"

BetaRequestCharLocationCitationobject

cited_text*	string
document_index*	integer	n ≥ 0
document_title*	string	length ≥ 1 · length ≤ 500 · nullable
end_char_index*	integer
start_char_index*	integer	n ≥ 0
type*	const	"char_location"

BetaRequestCitationsConfigobject

enabled

boolean

BetaRequestCodeExecutionOutputBlockobject

file_id*	string
type*	const		"code_execution_output"

BetaRequestCodeExecutionResultBlockobject

content*	BetaRequestCodeExecutionOutputBlock[]
return_code*	integer
stderr*	string
stdout*	string
type*	const	"code_execution_result"

BetaRequestCodeExecutionToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	Error \| Result Block \| RequestEncryptedCodeExecutionResultBlock
tool_use_id*	string
type*	const		"code_execution_tool_result"

BetaRequestCodeExecutionToolResultErrorobject

error_code*	enum		invalid_tool_input \| unavailable \| too_many_requests \| execution_time_exceeded
type*	const		"code_execution_tool_result_erro…

BetaRequestCompactionBlockobject

A compaction block containing summary of previous context.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content	string	Summary of previously compacted content, or null if compaction failed	nullable
encrypted_content	string	Opaque metadata from prior compaction, to be round-tripped verbatim	nullable
signature	string	The block's signature as returned, to be sent back verbatim	nullable
tool_changes	BetaRequestToolAdditionBlock \| BetaRequestToolRemovalBlock[]	The tool changes of the compacted range, as the server returned them on this block: the `tool_addition` and `tool_removal` entries that take the request's `tools` to the tool set in effect at the end of the range. Send them back unchanged with the block.	nullable
type*	const		"compaction"

BetaRequestContainerUploadBlockobject

A content block that represents a file to be uploaded to the container Files uploaded via this block will be available in the container's input directory.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
file_id*	string
type*	const		"container_upload"

BetaRequestContentBlockLocationCitationobject

cited_text*	string	The full text of the cited block range, concatenated.
document_index*	integer		n ≥ 0
document_title*	string		length ≥ 1 · length ≤ 500 · nullable
end_block_index*	integer	Exclusive 0-based end index of the cited block range in the source's `content` array.
start_block_index*	integer	0-based index of the first cited block in the source's `content` array.	n ≥ 0
type*	const		"content_block_location"

BetaRequestDocumentBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig		nullable
context	string		length ≥ 1 · nullable
source*	Base64PDFSource \| PlainTextSource \| ContentBlockSource \| …
title	string		length ≥ 1 · length ≤ 500 · nullable
type*	const		"document"

BetaRequestEncryptedCodeExecutionResultBlockobject

The output and exit code of Python code that Claude ran with the code execution tool, with standard output in encrypted form, sent back in a later request.

content*	BetaRequestCodeExecutionOutputBlock[]
encrypted_stdout*	string
return_code*	integer
stderr*	string
type*	const	"encrypted_code_execution_result…

BetaRequestFallbackBlockobject

A `fallback` block echoed back from a prior response.

from*	BetaRequestFallbackHopInfo	Identifies one hop of a fallback transition.
to*	BetaRequestFallbackHopInfo	Identifies one hop of a fallback transition.
trigger	any	The response block's `trigger`, echoed verbatim. Accepted and ignored by the server; any object or `null` is allowed.
type*	const		"fallback"

BetaRequestFallbackHopInfoobject

Identifies one hop of a fallback transition.

model*

string

The model that will complete your prompt.

22 known values

BetaRequestImageBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
source*	Base64ImageSource \| URLImageSource \| FileImageSource
transformations	BetaRequestImageTransformations	Configures the transformations the server applies to this image before the model observes it. Each key names a condition the server transforms images for; its value selects the transformation applied. Omitted keys keep their default behavior, and an empty obje…	nullable
type*	const		"image"

BetaRequestImageTransformationsobject

Configures the transformations the server applies to this image before the model observes it. Each key names a condition the server transforms images for; its value selects the transformation applied. Omitted keys keep their default behavior, and an empty obje…

oversized_image

enum

What the server does when this image exceeds the model's maximum image size. `"downsize"` (the default) scales the image down to fit, which changes the dimensions the model observes without telling you. `"error"` instead rejects the request with a 400 error na…

downsize | error

BetaRequestMCPServerToolConfigurationobject

allowed_tools	string[]		nullable
enabled	boolean		nullable

BetaRequestMCPServerURLDefinitionobject

authorization_token	string	nullable
name*	string
tool_configuration	BetaRequestMCPServerToolConfiguration	nullable
type*	const	"url"
url*	string

BetaRequestMCPToolListingBlockobject

The tool listing an MCP server returned while an earlier response was produced, as that response carried it. Send the assistant message back unchanged, this block included, and the server uses this listing for the matching `mcp_toolset` instead of asking the M…

mcp_server_name*	string	The name of the MCP server this listing came from, as `mcp_servers` declares it.	length ≥ 1 · length ≤ 255
tools*	BetaMCPTool[]	The server's tools, exactly as the response listed them.
type*	const		"mcp_tool_listing"

BetaRequestMCPToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content	string \| BetaRequestTextBlock[]
is_error	boolean
tool_use_id*	string
type*	const		"mcp_tool_result"

BetaRequestMCPToolUseBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
id*	string
input*	object
name*	string
server_name*	string	The name of the MCP server
type*	const		"mcp_tool_use"

BetaRequestPageLocationCitationobject

cited_text*	string
document_index*	integer	n ≥ 0
document_title*	string	length ≥ 1 · length ≤ 500 · nullable
end_page_number*	integer
start_page_number*	integer	n ≥ 1
type*	const	"page_location"

BetaRequestRedactedThinkingBlockobject

data*	string	The `data` value of this redacted thinking block, exactly as returned by the API in a previous response. Opaque and encrypted; pass it back unchanged.
type*	const		"redacted_thinking"

BetaRequestSearchResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig
content*	BetaRequestTextBlock[]
source*	string
title*	string
type*	const		"search_result"

BetaRequestSearchResultLocationCitationobject

cited_text*	string	The full text of the cited block range, concatenated.
end_block_index*	integer	Exclusive 0-based end index of the cited block range in the source's `content` array.
search_result_index*	integer	0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.	n ≥ 0
source*	string
start_block_index*	integer	0-based index of the first cited block in the source's `content` array.	n ≥ 0
title*	string		nullable
type*	const		"search_result_location"

BetaRequestServerToolUseBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caller	DirectCaller \| ServerToolCaller \| ServerToolCaller_20260120
id*	string
input*	object
name*	enum		advisor \| web_search \| web_fetch \| code_execution \| bash_code_execution \| text_editor_code_execution · +2 more
type*	const		"server_tool_use"

BetaRequestTextBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCharLocationCitation \| BetaRequestPageLocationCitation \| BetaRequestContentBlockLocationCitation[]		nullable
text*	string		length ≥ 1
type*	const		"text"

BetaRequestTextEditorCodeExecutionCreateResultBlockobject

is_file_update*	boolean
type*	const		"text_editor_code_execution_crea…

BetaRequestTextEditorCodeExecutionStrReplaceResultBlockobject

lines	string[]	nullable
new_lines	integer	nullable
new_start	integer	nullable
old_lines	integer	nullable
old_start	integer	nullable
type*	const	"text_editor_code_execution_str_…

BetaRequestTextEditorCodeExecutionToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	RequestTextEditorCodeExecutionToolResultError \| RequestTextEditorCodeExecutionViewResultBlock \| RequestTextEditorCodeExecutionCreateResultBlock \| …
tool_use_id*	string
type*	const		"text_editor_code_execution_tool…

BetaRequestTextEditorCodeExecutionToolResultErrorobject

error_code*	enum	invalid_tool_input \| unavailable \| too_many_requests \| execution_time_exceeded \| file_not_found
error_message	string	nullable
type*	const	"text_editor_code_execution_tool…

BetaRequestTextEditorCodeExecutionViewResultBlockobject

content*	string
file_type*	enum	text \| image \| pdf
num_lines	integer	nullable
start_line	integer	nullable
total_lines	integer	nullable
type*	const	"text_editor_code_execution_view…

BetaRequestThinkingBlockobject

signature*	string	The `signature` value of this thinking block, exactly as returned by the API in a previous response. Used to verify that the block was generated by Claude.
thinking*	string	The `thinking` text of this block as returned by the API.
type*	const		"thinking"

BetaRequestToolAdditionBlockobject

Mid-conversation directive to make a tool available.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
tool*	ToolChangeToolReference \| ToolChangeMCPToolReference \| ToolChangeMCPToolsetReference \| …
type*	const		"tool_addition"

BetaRequestToolReferenceBlockobject

Tool reference block that can be included in tool_result content.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
tool_name*	string		length ≥ 1 · length ≤ 256
type*	const		"tool_reference"

BetaRequestToolRemovalBlockobject

Mid-conversation directive to withdraw a tool.

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
tool*	ToolChangeToolReference \| ToolChangeMCPToolReference \| ToolChangeMCPToolsetReference
type*	const		"tool_removal"

BetaRequestToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content	string \| BetaRequestTextBlock \| BetaRequestImageBlock \| BetaRequestSearchResultBlock[]
is_error	boolean
tool_use_id*	string
toolset_name	string	For a toolset member tool_result, the toolset family of the paired tool_use.	length ≥ 1 · length ≤ 64 · nullable
type*	const		"tool_result"

BetaRequestToolSearchToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	RequestToolSearchToolResultError \| RequestToolSearchToolSearchResultBlock
tool_use_id*	string
type*	const		"tool_search_tool_result"

BetaRequestToolSearchToolResultErrorobject

error_code*	enum	invalid_tool_input \| unavailable \| too_many_requests \| execution_time_exceeded
error_message	string	nullable
type*	const	"tool_search_tool_result_error"

BetaRequestToolSearchToolSearchResultBlockobject

tool_references*	BetaRequestToolReferenceBlock[]
type*	const		"tool_search_tool_search_result"

BetaRequestToolUseBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caller	DirectCaller \| ServerToolCaller \| ServerToolCaller_20260120
id*	string
input*	object
name*	string		length ≥ 1 · length ≤ 200
toolset_name	string	For a toolset member tool_use, the toolset family this member belongs to.	length ≥ 1 · length ≤ 64 · nullable
type*	const		"tool_use"

BetaRequestWebFetchResultBlockobject

content*	BetaRequestDocumentBlock
retrieved_at	string	ISO 8601 timestamp when the content was retrieved	nullable
type*	const		"web_fetch_result"
url*	string	Fetched content URL

BetaRequestWebFetchToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caller	DirectCaller \| ServerToolCaller \| ServerToolCaller_20260120
content*	RequestWebFetchToolResultError \| RequestWebFetchResultBlock
tool_use_id*	string
type*	const		"web_fetch_tool_result"

BetaRequestWebFetchToolResultErrorobject

error_code*	enum		invalid_tool_input \| url_too_long \| url_not_allowed \| url_not_in_prior_context \| url_not_accessible \| unsupported_content_type · +4 more
type*	const		"web_fetch_tool_result_error"

BetaRequestWebSearchResultBlockobject

encrypted_content*	string
page_age	string	nullable
title*	string
type*	const	"web_search_result"
url*	string

BetaRequestWebSearchResultLocationCitationobject

cited_text*	string
encrypted_index*	string
title*	string	length ≥ 1 · length ≤ 512 · nullable
type*	const	"web_search_result_location"
url*	string	length ≥ 1

BetaRequestWebSearchToolResultBlockobject

cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caller	DirectCaller \| ServerToolCaller \| ServerToolCaller_20260120
content*	BetaRequestWebSearchResultBlock[] \| Error
tool_use_id*	string
type*	const		"web_search_tool_result"

BetaRequestWebSearchToolResultErrorobject

error_code*	enum		invalid_tool_input \| unavailable \| max_uses_exceeded \| too_many_requests \| query_too_long \| request_too_large
type*	const		"web_search_tool_result_error"

BetaServerToolCallerobject

Tool invocation generated by a server-side tool.

tool_id*	string
type*	const		"code_execution_20250825"

BetaServerToolCaller_20260120object

tool_id*	string
type*	const		"code_execution_20260120"

BetaSkillParamsobject

Specification for a skill to be loaded in a container.

skill_id*	string	Skill ID	length ≥ 1 · length ≤ 64
type*	enum	Type of skill - either 'anthropic' (built-in) or 'custom' (user-defined)	anthropic \| custom
version	string	Skill version or 'latest' for most recent version	length ≥ 1 · length ≤ 64

BetaSpeedenum

standard | fast

BetaSummarizeCompactionobject

instructions	string	Replaces the server's default summarization prompt for this request. An empty or whitespace-only value counts as absent.	length ≤ 16384 · nullable
type*	const		"summarize"

BetaSystemInputMessageobject

clear_at	enum	How long this system message's text stays in front of the model. `"never"` (the default) renders it on every request that includes it. `"next_user_message"` renders it only for the user turn it follows: once a later `role: "user"` message exists in `messages` the message stays in the array (send it unchanged) but is no longer shown to the model. Only permitted on `role: "system"` messages.	next_user_message \| never · nullable
content	string \| BetaRequestTextBlock \| BetaRequestToolAdditionBlock \| BetaRequestToolRemovalBlock[]
output_config	BetaSystemMessageOutputConfig	Per-message output configuration on a role:"system" input message.	nullable
role*	const		"system"

BetaSystemMessageOutputConfigobject

Per-message output configuration on a role:"system" input message.

effort

enum

All possible effort levels.

low | medium | high | xhigh | max · nullable

BetaTextEditor_20241022object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"str_replace_editor"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"text_editor_20241022"

BetaTextEditor_20250124object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"str_replace_editor"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"text_editor_20250124"

BetaTextEditor_20250429object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
name*	const	Name of the tool.	"str_replace_based_edit_tool"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"text_editor_20250429"

BetaTextEditor_20250728object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]
max_characters	integer	Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.	n ≥ 1 · nullable
name*	const	Name of the tool.	"str_replace_based_edit_tool"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"text_editor_20250728"

BetaTextEditorCodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded | file_not_found

BetaThinkingBlockBindingobject

Controls for block binding: what happens when a thinking block this request sends back fails the conversation check. Every field is optional; an empty object means every default.

prefix_mismatch_behavior

enum

What happens when a thinking block in `messages` fails the conversation check: it was created in a different conversation, or the messages before it have changed since. `"error"` (the default) fails the request with a 400 error. `"drop_block"` removes the fail…

error | drop_block · nullable

BetaThinkingConfigAdaptiveobject

block_binding	BetaThinkingBlockBinding	Controls for block binding: what happens when a thinking block this request sends back fails the conversation check. Every field is optional; an empty object means every default.	nullable
display	enum	Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. The default depends on the model; see [Controlling thinking display](https://platform.claude.com/docs/en/build-with-claude/thinking#controlling-thinking-display).	summarized \| omitted \| updates · nullable
type*	const		"adaptive"

BetaThinkingConfigBetweenToolsobject

type*

const

"between_tools"

BetaThinkingConfigDisabledobject

type*

const

"disabled"

BetaThinkingConfigEnabledobject

block_binding	BetaThinkingBlockBinding	Controls for block binding: what happens when a thinking block this request sends back fails the conversation check. Every field is optional; an empty object means every default.	nullable
budget_tokens*	integer	Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.	n ≥ 1024
display	enum	Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. The default depends on the model; see [Controlling thinking display](https://platform.claude.com/docs/en/build-with-claude/thinking#controlling-thinking-display).	summarized \| omitted \| updates · nullable
type*	const		"enabled"

BetaThinkingConfigParamThinkingConfigEnabled | ThinkingConfigDisabled | ThinkingConfigBetweenTools | …

Configuration for Claude's thinking.

BetaThinkingDisplayModeenum

summarized | omitted | updates

BetaThinkingPrefixMismatchBehaviorenum

error | drop_block

BetaThinkingTurnsobject

type*	const		"thinking_turns"
value*	integer		n ≥ 1

BetaThreadContinueParamsobject

Resume from the response named by ``previous_message_id``.

previous_message_id*	string	The `id` of the previous response in this Thread.
type*	const		"continue"

BetaThreadCreateParamsobject

Start holding conversation state under this response's ``id``.

type*

const

"create"

BetaTokenTaskBudgetobject

User-configurable total token budget across contexts.

remaining	integer	Remaining tokens in the budget. Use this to track usage across contexts when implementing compaction client-side. Defaults to total if not provided.	n ≥ 0 · nullable
total*	integer	Total token budget across all contexts in the session.	n ≥ 1024
type*	const	The budget type. Currently only 'tokens' is supported.	"tokens"

BetaToolobject

type	const		"custom" · nullable
description	string	Description of what this tool does.
name*	string	Name of the tool.	length ≥ 1 · length ≤ 128
input_schema*	BetaInputSchema	[JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
strict	boolean	When true, guarantees schema validation on tool names and inputs
eager_input_streaming	boolean	Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.	nullable
allowed_callers	BetaAllowedCaller[]
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
input_examples	object[]

BetaToolChangeMCPToolReferenceobject

Reference to a single MCP tool by its server and remote name; the same ``server_name``/``name`` pair ``mcp_tool_use`` carries.

name*	string
server_name*	string
type*	const	"mcp_tool_reference"

BetaToolChangeMCPToolsetReferenceobject

Reference to every tool in the named MCP server's toolset.

server_name*	string
type*	const		"mcp_toolset_reference"

BetaToolChangeToolDefinitionobject

A tool defined by value: `definition` is a `tools` entry (any kind `tools` accepts, an MCP toolset included). An `mcp_toolset` given here also requires the `mcp-client-2026-09-15` beta.

definition*	Tool \| BashTool_20241022 \| BashTool_20250124 \| …
type*	const		"tool_definition"

BetaToolChangeToolReferenceobject

Reference to a single tool, by the name the model uses to call it: a tool declared in ``tools`` or defined by an earlier ``tool_addition`` block. Does not accept the composed ``{server}_{name}`` form the server assigns to MCP-resolved tools; use ``mcp_tool_ref…

name*	string
type*	const		"tool_reference"

BetaToolChoiceToolChoiceAuto | ToolChoiceAny | ToolChoiceTool | …

How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

BetaToolChoiceAnyobject

The model will use any available tools.

disable_parallel_tool_use	boolean	Whether to disable parallel tool use.
type*	const		"any"

BetaToolChoiceAutoobject

The model will automatically decide whether to use tools.

disable_parallel_tool_use	boolean	Whether to disable parallel tool use.
type*	const		"auto"

BetaToolChoiceNoneobject

The model will not be allowed to use tools.

type*

const

"none"

BetaToolChoiceToolobject

The model will use the specified tool with `tool_choice.name`.

disable_parallel_tool_use	boolean	Whether to disable parallel tool use.
name*	string	The name of the tool to use.
type*	const		"tool"

BetaToolSearchToolBM25_20251119object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"tool_search_tool_bm25"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	enum		tool_search_tool_bm25_20251119 \| tool_search_tool_bm25

BetaToolSearchToolRegex_20251119object

allowed_callers	BetaAllowedCaller[]
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
name*	const	Name of the tool.	"tool_search_tool_regex"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	enum		tool_search_tool_regex_20251119… \| tool_search_tool_regex

BetaToolSearchToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded

BetaToolUnionTool | BashTool_20241022 | BashTool_20250124 | …

BetaToolUsesKeepobject

type*	const		"tool_uses"
value*	integer		n ≥ 0

BetaToolUsesTriggerobject

type*	const		"tool_uses"
value*	integer		n ≥ 1

BetaURLImageSourceobject

type*	const		"url"
url*	string

BetaURLPDFSourceobject

type*	const		"url"
url*	string

BetaUserInputMessageobject

content*	string \| BetaInputContentBlock[]
role*	const		"user"

BetaUserLocationobject

city	string	The city of the user.	length ≥ 1 · length ≤ 255 · nullable
country	string	The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.	length ≥ 2 · length ≤ 2 · nullable
region	string	The region of the user.	length ≥ 1 · length ≤ 255 · nullable
timezone	string	The [IANA timezone](https://nodatime.org/TimeZones) of the user.	length ≥ 1 · length ≤ 255 · nullable
type*	const		"approximate"

BetaWebFetchTool_20250910object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig	Citations configuration for fetched documents. Citations are disabled by default.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_content_tokens	integer	Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.	n > 0 · nullable
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_fetch"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_fetch_20250910"
url_sources	BetaWebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable

BetaWebFetchTool_20260209object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig	Citations configuration for fetched documents. Citations are disabled by default.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_content_tokens	integer	Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.	n > 0 · nullable
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_fetch"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_fetch_20260209"
url_sources	BetaWebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable

BetaWebFetchTool_20260309object

Web fetch tool with use_cache parameter for bypassing cached content.

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig	Citations configuration for fetched documents. Citations are disabled by default.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_content_tokens	integer	Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.	n > 0 · nullable
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_fetch"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_fetch_20260309"
url_sources	BetaWebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable
use_cache	boolean	Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

BetaWebFetchTool_20260318object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	BetaRequestCitationsConfig	Citations configuration for fetched documents. Citations are disabled by default.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_content_tokens	integer	Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.	n > 0 · nullable
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_fetch"
response_inclusion	enum	How this tool's result blocks appear in the API response when the result was consumed by a completed code_execution call in the same turn. 'full' returns the complete content (default). 'excluded' drops the nested server_tool_use and result block pair entirely…	full \| excluded
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_fetch_20260318"
url_sources	BetaWebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable
use_cache	boolean	Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

BetaWebFetchToolResultErrorCodeenum

BetaWebFetchUrlSourceAllobject

The ``url_sources`` variant under which a source contributes in full: every result of the tool filter's source, or all user input.

type*

const

"all"

BetaWebFetchUrlSourceExceptobject

The tool filter variant under which every result but the named tools' contributes.

tools*	BetaWebFetchUrlSourceToolReference[]
type*	const		"except"

BetaWebFetchUrlSourceNoneobject

The ``url_sources`` variant under which a source contributes nothing: no result of the tool filter's source, or no user input.

type*

const

"none"

BetaWebFetchUrlSourceOnlyobject

The tool filter variant under which only the named tools' results contribute.

tools*	BetaWebFetchUrlSourceToolReference[]
type*	const		"only"

BetaWebFetchUrlSourcesobject

Which sources contribute to the set of URLs web fetch may fetch.

client_tool_results	WebFetchUrlSourceAll \| WebFetchUrlSourceNone \| WebFetchUrlSourceOnly \| …	Which client tools' results contribute fetchable URLs: "all", "none", or an only or except list of client tool names from tools[].
server_tool_results	WebFetchUrlSourceAll \| WebFetchUrlSourceNone \| WebFetchUrlSourceOnly \| …	Which server tools' results contribute fetchable URLs: "all", "none", or an only or except list of server tool names from tools[]; only web_search and web_fetch results ever contribute.
user_input	WebFetchUrlSourceAll \| WebFetchUrlSourceNone	Whether URLs in user messages are fetchable: "all" or "none".

BetaWebFetchUrlSourceToolReferenceobject

One entry of a tool filter's ``tools``: it must name a tool declared in this request's ``tools[]``.

name*	string
type*	const		"tool_reference"

BetaWebSearchTool_20250305object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.	nullable
blocked_domains	string[]	If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_search"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_search_20250305"
user_location	BetaUserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

BetaWebSearchTool_20260209object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.	nullable
blocked_domains	string[]	If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_search"
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_search_20260209"
user_location	BetaUserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

BetaWebSearchTool_20260318object

allowed_callers	BetaAllowedCaller[]
allowed_domains	string[]	If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.	nullable
blocked_domains	string[]	If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.	nullable
cache_control	BetaCacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
defer_loading	boolean	If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.
max_uses	integer	Maximum number of times the tool can be used in the API request.	n > 0 · nullable
name*	const	Name of the tool.	"web_search"
response_inclusion	enum	How this tool's result blocks appear in the API response when the result was consumed by a completed code_execution call in the same turn. 'full' returns the complete content (default). 'excluded' drops the nested server_tool_use and result block pair entirely…	full \| excluded
strict	boolean	When true, guarantees schema validation on tool names and inputs
type*	const		"web_search_20260318"
user_location	BetaUserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

BetaWebSearchToolResultErrorCodeenum

Modelstring

The model that will complete your prompt.

22 known values

Validate a payload

before you spend tokens

shell

$ curl -X POST https://modelschemas.com/v1/validate \
    -d '{"provider":"anthropic","endpointId":"v1/messages?beta=true","payload":{…}}'
→ {"valid": false, "errors": [{"path": "#", "keyword": "required", …}]}

/v1/schemas/anthropic/chat/v1/messages?beta=true

Request body

Types

BetaAdvisorTool_20260301object

BetaAdvisorToolResultErrorCodeenum

BetaAllowedCallerenum

BetaAllThinkingTurnsobject

BetaAssistantInputMessageobject

BetaBase64ImageSourceobject

BetaBase64PDFSourceobject

BetaBashCodeExecutionToolResultErrorCodeenum

BetaBashTool_20241022object

BetaBashTool_20250124object

BetaBrowserCloseTabConfigobject

BetaBrowserDoubleClickConfigobject

BetaBrowserFileUploadConfigobject

BetaBrowserFindConfigobject

BetaBrowserFormInputConfigobject

BetaBrowserGetPageTextConfigobject

BetaBrowserHoldKeyConfigobject

BetaBrowserHoverConfigobject

BetaBrowserJavascriptExecConfigobject

BetaBrowserKeyConfigobject

BetaBrowserLeftClickConfigobject

BetaBrowserLeftClickDragConfigobject

BetaBrowserLeftMouseDownConfigobject

BetaBrowserLeftMouseUpConfigobject

BetaBrowserListTabsConfigobject

BetaBrowserMiddleClickConfigobject

BetaBrowserMouseMoveConfigobject

BetaBrowserNavigateConfigobject

BetaBrowserNewTabConfigobject

BetaBrowserReadConsoleConfigobject

BetaBrowserReadNetworkConfigobject

BetaBrowserReadPageConfigobject

BetaBrowserRightClickConfigobject

BetaBrowserScreenshotConfigobject

BetaBrowserScrollConfigobject

BetaBrowserScrollToConfigobject

BetaBrowserStateChangeDownloadCompletedobject

BetaBrowserStateChangeDownloadFailedobject

BetaBrowserStateChangeDownloadStartedobject

BetaBrowserStateChangeTabOpenedobject

BetaBrowserStateTabEntryobject

BetaBrowserSwitchTabConfigobject

BetaBrowserToolset_20260801object

BetaBrowserToolsetConfigsobject

BetaBrowserTripleClickConfigobject

BetaBrowserTypeConfigobject

BetaBrowserWaitConfigobject

BetaBrowserZoomConfigobject

BetaCacheControlEphemeralobject

BetaClearThinking20251015object

BetaClearToolUses20250919object

BetaCodeExecutionTool_20250522object

BetaCodeExecutionTool_20250825object

BetaCodeExecutionTool_20260120object

BetaCodeExecutionTool_20260521object

BetaCodeExecutionToolResultErrorCodeenum

BetaCompact20260112object

BetaCompactionConfigBetaSummarizeCompaction

BetaComputerCursorPositionConfigobject

BetaComputerDoubleClickConfigobject

BetaComputerHoldKeyConfigobject

BetaComputerKeyConfigobject

BetaComputerLeftClickConfigobject

BetaComputerLeftClickDragConfigobject

BetaComputerLeftMouseDownConfigobject

BetaComputerLeftMouseUpConfigobject

BetaComputerMiddleClickConfigobject

BetaComputerMouseMoveConfigobject

BetaComputerRightClickConfigobject

BetaComputerScreenshotConfigobject

BetaComputerScrollConfigobject

BetaComputerToolset_20260801object

BetaComputerToolsetConfigsobject

BetaComputerTripleClickConfigobject

BetaComputerTypeConfigobject

BetaComputerUseTool_20241022object

BetaComputerUseTool_20250124object