GET

/v1/schemas/anthropic/chat/v1/messages/count_tokens

Accept:

kind inputactivity chathash eed6430c…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

9 properties · 2 required · 168 $defs

property	type	description	constraints
messages*	InputMessageUnion[]	Input messages.
model*	string	The model that will complete your prompt.	22 known values
cache_control	CacheControlEphemeral	Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.	nullable
output_config	OutputConfig	Configuration options for the model's output, such as the output format.
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
system	string \| RequestTextBlock[]	System prompt.
thinking	ThinkingConfigEnabled \| ThinkingConfigDisabled \| ThinkingConfigBetweenTools \| …	Configuration for Claude's thinking.
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	Tool \| BashTool_20250124 \| CodeExecutionTool_20250522[]	Definitions of tools that the model may use.

Types

168 $defs

AllowedCallerenum

Specifies who can invoke a tool.

direct | code_execution_20250825 | code_execution_20260120 | code_execution_20260521

AssistantInputMessageobject

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

Base64ImageSourceobject

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

Base64PDFSourceobject

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

BashCodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded | output_file_too_large

BashTool_20250124object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

BrowserCloseTabConfigobject

``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

BrowserDoubleClickConfigobject

``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

BrowserFileUploadConfigobject

``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

BrowserFindConfigobject

``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

BrowserFormInputConfigobject

``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

BrowserGetPageTextConfigobject

``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

BrowserHoldKeyConfigobject

``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

BrowserHoverConfigobject

``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

BrowserJavascriptExecConfigobject

``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

BrowserKeyConfigobject

``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

BrowserLeftClickConfigobject

``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

BrowserLeftClickDragConfigobject

``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

BrowserLeftMouseDownConfigobject

``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

BrowserLeftMouseUpConfigobject

``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

BrowserListTabsConfigobject

``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

BrowserMiddleClickConfigobject

``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

BrowserMouseMoveConfigobject

``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

BrowserNavigateConfigobject

``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

BrowserNewTabConfigobject

``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

BrowserReadConsoleConfigobject

``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

BrowserReadNetworkConfigobject

``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

BrowserReadPageConfigobject

``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

BrowserRightClickConfigobject

``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

BrowserScreenshotConfigobject

``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

BrowserScrollConfigobject

``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

BrowserScrollToConfigobject

``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

BrowserStateChangeDownloadCompletedobject

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

BrowserStateChangeDownloadFailedobject

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

BrowserStateChangeDownloadStartedobject

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

BrowserStateChangeTabOpenedobject

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"

BrowserStateTabEntryobject

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

BrowserSwitchTabConfigobject

``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

BrowserToolset_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	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
configs	BrowserToolsetConfigs	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"

BrowserToolsetConfigsobject

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	BrowserCloseTabConfig	``close_tab``'s config overrides.	nullable
double_click	BrowserDoubleClickConfig	``double_click``'s config overrides.	nullable
file_upload	BrowserFileUploadConfig	``file_upload``'s config overrides.	nullable
find	BrowserFindConfig	``find``'s config overrides.	nullable
form_input	BrowserFormInputConfig	``form_input``'s config overrides.	nullable
get_page_text	BrowserGetPageTextConfig	``get_page_text``'s config overrides.	nullable
hold_key	BrowserHoldKeyConfig	``hold_key``'s config overrides.	nullable
hover	BrowserHoverConfig	``hover``'s config overrides.	nullable
javascript_exec	BrowserJavascriptExecConfig	``javascript_exec``'s config overrides.	nullable
key	BrowserKeyConfig	``key``'s config overrides.	nullable
left_click	BrowserLeftClickConfig	``left_click``'s config overrides.	nullable
left_click_drag	BrowserLeftClickDragConfig	``left_click_drag``'s config overrides.	nullable
left_mouse_down	BrowserLeftMouseDownConfig	``left_mouse_down``'s config overrides.	nullable
left_mouse_up	BrowserLeftMouseUpConfig	``left_mouse_up``'s config overrides.	nullable
list_tabs	BrowserListTabsConfig	``list_tabs``'s config overrides.	nullable
middle_click	BrowserMiddleClickConfig	``middle_click``'s config overrides.	nullable
mouse_move	BrowserMouseMoveConfig	``mouse_move``'s config overrides.	nullable
navigate	BrowserNavigateConfig	``navigate``'s config overrides.	nullable
new_tab	BrowserNewTabConfig	``new_tab``'s config overrides.	nullable
read_console	BrowserReadConsoleConfig	``read_console``'s config overrides.	nullable
read_network	BrowserReadNetworkConfig	``read_network``'s config overrides.	nullable
read_page	BrowserReadPageConfig	``read_page``'s config overrides.	nullable
right_click	BrowserRightClickConfig	``right_click``'s config overrides.	nullable
screenshot	BrowserScreenshotConfig	``screenshot``'s config overrides.	nullable
scroll	BrowserScrollConfig	``scroll``'s config overrides.	nullable
scroll_to	BrowserScrollToConfig	``scroll_to``'s config overrides.	nullable
switch_tab	BrowserSwitchTabConfig	``switch_tab``'s config overrides.	nullable
triple_click	BrowserTripleClickConfig	``triple_click``'s config overrides.	nullable
type	BrowserTypeConfig	``type``'s config overrides.	nullable
wait	BrowserWaitConfig	``wait``'s config overrides.	nullable
zoom	BrowserZoomConfig	``zoom``'s config overrides.	nullable

BrowserTripleClickConfigobject

``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

BrowserTypeConfigobject

``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

BrowserWaitConfigobject

``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

BrowserZoomConfigobject

``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

CacheControlEphemeralobject

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

CodeExecutionTool_20250522object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

CodeExecutionTool_20250825object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

CodeExecutionTool_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	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

CodeExecutionTool_20260521object

Code execution tool with REPL state persistence.

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

CodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded

ComputerCursorPositionConfigobject

``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

ComputerDoubleClickConfigobject

``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

ComputerHoldKeyConfigobject

``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

ComputerKeyConfigobject

``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

ComputerLeftClickConfigobject

``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

ComputerLeftClickDragConfigobject

``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

ComputerLeftMouseDownConfigobject

``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

ComputerLeftMouseUpConfigobject

``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

ComputerMiddleClickConfigobject

``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

ComputerMouseMoveConfigobject

``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

ComputerRightClickConfigobject

``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

ComputerScreenshotConfigobject

``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

ComputerScrollConfigobject

``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

ComputerToolset_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	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
configs	ComputerToolsetConfigs	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"

ComputerToolsetConfigsobject

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	ComputerCursorPositionConfig	``cursor_position``'s config overrides.	nullable
double_click	ComputerDoubleClickConfig	``double_click``'s config overrides.	nullable
hold_key	ComputerHoldKeyConfig	``hold_key``'s config overrides.	nullable
key	ComputerKeyConfig	``key``'s config overrides.	nullable
left_click	ComputerLeftClickConfig	``left_click``'s config overrides.	nullable
left_click_drag	ComputerLeftClickDragConfig	``left_click_drag``'s config overrides.	nullable
left_mouse_down	ComputerLeftMouseDownConfig	``left_mouse_down``'s config overrides.	nullable
left_mouse_up	ComputerLeftMouseUpConfig	``left_mouse_up``'s config overrides.	nullable
middle_click	ComputerMiddleClickConfig	``middle_click``'s config overrides.	nullable
mouse_move	ComputerMouseMoveConfig	``mouse_move``'s config overrides.	nullable
right_click	ComputerRightClickConfig	``right_click``'s config overrides.	nullable
screenshot	ComputerScreenshotConfig	``screenshot``'s config overrides.	nullable
scroll	ComputerScrollConfig	``scroll``'s config overrides.	nullable
triple_click	ComputerTripleClickConfig	``triple_click``'s config overrides.	nullable
type	ComputerTypeConfig	``type``'s config overrides.	nullable
wait	ComputerWaitConfig	``wait``'s config overrides.	nullable
zoom	ComputerZoomConfig	``zoom``'s config overrides.	nullable

ComputerTripleClickConfigobject

``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

ComputerTypeConfigobject

``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

ComputerWaitConfigobject

``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

ComputerZoomConfigobject

``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

ContentBlockSourceobject

content*	string \| RequestTextBlock \| RequestImageBlock[]
type*	const		"content"

DirectCallerobject

Tool invocation directly from the model.

type*

const

"direct"

EffortLevelenum

All possible effort levels.

low | medium | high | xhigh | max

FileDocumentSourceobject

file_id*	string
type*	const		"file"

FileImageSourceobject

file_id*	string
type*	const		"file"

InputContentBlockRequestTextBlock | RequestImageBlock | RequestDocumentBlock | …

InputMessageContentstring | InputContentBlock[]

InputMessageUnionUserInputMessage | AssistantInputMessage | SystemInputMessage

InputSchemaobject

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

JsonOutputFormatobject

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

JsonValueany

MemoryTool_20250818object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

Modelstring

The model that will complete your prompt.

22 known values

OutputConfigobject

effort	enum	All possible effort levels.	low \| medium \| high \| xhigh \| max · nullable
format	JsonOutputFormat	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

PlainTextSourceobject

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

RequestBashCodeExecutionOutputBlockobject

file_id*	string
type*	const		"bash_code_execution_output"

RequestBashCodeExecutionResultBlockobject

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

RequestBashCodeExecutionToolResultBlockobject

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

RequestBashCodeExecutionToolResultErrorobject

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

RequestBrowserStateBlockobject

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	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
state_changes	BrowserStateChangeTabOpened \| BrowserStateChangeDownloadStarted \| BrowserStateChangeDownloadCompleted[]	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*	BrowserStateTabEntry[]	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"

RequestCharLocationCitationobject

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"

RequestCitationsConfigobject

enabled

boolean

RequestCodeExecutionOutputBlockobject

file_id*	string
type*	const		"code_execution_output"

RequestCodeExecutionResultBlockobject

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

RequestCodeExecutionToolResultBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content*	RequestCodeExecutionToolResultError \| RequestCodeExecutionResultBlock \| RequestEncryptedCodeExecutionResultBlock
tool_use_id*	string
type*	const		"code_execution_tool_result"

RequestCodeExecutionToolResultErrorobject

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

RequestContainerUploadBlockobject

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

RequestContentBlockLocationCitationobject

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"

RequestDocumentBlockobject

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

RequestEncryptedCodeExecutionResultBlockobject

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

RequestImageBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
source*	Base64ImageSource \| URLImageSource \| FileImageSource
transformations	RequestImageTransformations	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"

RequestImageTransformationsobject

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

RequestPageLocationCitationobject

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"

RequestRedactedThinkingBlockobject

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"

RequestSearchResultBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCitationsConfig
content*	RequestTextBlock[]
source*	string
title*	string
type*	const		"search_result"

RequestSearchResultLocationCitationobject

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"

RequestServerToolUseBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
caller	DirectCaller \| ServerToolCaller \| ServerToolCaller_20260120
id*	string
input*	object
name*	enum		web_search \| web_fetch \| code_execution \| bash_code_execution \| text_editor_code_execution \| tool_search_tool_regex · +1 more
type*	const		"server_tool_use"

RequestTextBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCharLocationCitation \| RequestPageLocationCitation \| RequestContentBlockLocationCitation[]		nullable
text*	string		length ≥ 1
type*	const		"text"

RequestTextEditorCodeExecutionCreateResultBlockobject

is_file_update*	boolean
type*	const		"text_editor_code_execution_crea…

RequestTextEditorCodeExecutionStrReplaceResultBlockobject

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_…

RequestTextEditorCodeExecutionToolResultBlockobject

cache_control	CacheControlEphemeral	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…

RequestTextEditorCodeExecutionToolResultErrorobject

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…

RequestTextEditorCodeExecutionViewResultBlockobject

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…

RequestThinkingBlockobject

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"

RequestToolReferenceBlockobject

Tool reference block that can be included in tool_result content.

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

RequestToolResultBlockobject

cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
content	string \| RequestTextBlock \| RequestImageBlock \| RequestSearchResultBlock[]
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"

RequestToolSearchToolResultBlockobject

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

RequestToolSearchToolResultErrorobject

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

RequestToolSearchToolSearchResultBlockobject

tool_references*	RequestToolReferenceBlock[]
type*	const		"tool_search_tool_search_result"

RequestToolUseBlockobject

cache_control	CacheControlEphemeral	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"

RequestWebFetchResultBlockobject

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

RequestWebFetchToolResultBlockobject

cache_control	CacheControlEphemeral	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"

RequestWebFetchToolResultErrorobject

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"

RequestWebSearchResultBlockobject

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

RequestWebSearchResultLocationCitationobject

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

RequestWebSearchToolResultBlockobject

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

RequestWebSearchToolResultErrorobject

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"

ServerToolCallerobject

Tool invocation generated by a server-side tool.

tool_id*	string
type*	const		"code_execution_20250825"

ServerToolCaller_20260120object

tool_id*	string
type*	const		"code_execution_20260120"

Speedenum

standard | fast

SystemInputMessageobject

content*	string \| RequestTextBlock[]
role*	const		"system"

TextEditor_20250124object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

TextEditor_20250429object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

TextEditor_20250728object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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"

TextEditorCodeExecutionToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded | file_not_found

ThinkingConfigAdaptiveobject

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 · nullable
type*	const		"adaptive"

ThinkingConfigBetweenToolsobject

type*

const

"between_tools"

ThinkingConfigDisabledobject

type*

const

"disabled"

ThinkingConfigEnabledobject

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 · nullable
type*	const		"enabled"

ThinkingConfigParamThinkingConfigEnabled | ThinkingConfigDisabled | ThinkingConfigBetweenTools | …

Configuration for Claude's thinking.

ThinkingDisplayModeenum

summarized | omitted

Toolobject

type	const		"custom" · nullable
description	string	Description of what this tool does.
name*	string	Name of the tool.	length ≥ 1 · length ≤ 128
input_schema*	InputSchema	[JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.
cache_control	CacheControlEphemeral	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	AllowedCaller[]
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[]

ToolChoiceToolChoiceAuto | 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.

ToolChoiceAnyobject

The model will use any available tools.

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

ToolChoiceAutoobject

The model will automatically decide whether to use tools.

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

ToolChoiceNoneobject

The model will not be allowed to use tools.

type*

const

"none"

ToolChoiceToolobject

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"

ToolSearchToolBM25_20251119object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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

ToolSearchToolRegex_20251119object

allowed_callers	AllowedCaller[]
cache_control	CacheControlEphemeral	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

ToolSearchToolResultErrorCodeenum

invalid_tool_input | unavailable | too_many_requests | execution_time_exceeded

URLImageSourceobject

type*	const		"url"
url*	string

URLPDFSourceobject

type*	const		"url"
url*	string

UserInputMessageobject

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

UserLocationobject

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"

WebFetchTool_20250910object

allowed_callers	AllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCitationsConfig	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	WebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable

WebFetchTool_20260209object

allowed_callers	AllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCitationsConfig	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	WebFetchUrlSources	Which sources contribute to the set of URLs web fetch may fetch.	nullable

WebFetchTool_20260309object

Web fetch tool with use_cache parameter for bypassing cached content.

allowed_callers	AllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCitationsConfig	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	WebFetchUrlSources	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.

WebFetchTool_20260318object

allowed_callers	AllowedCaller[]
allowed_domains	string[]	List of domains to allow fetching from	nullable
blocked_domains	string[]	List of domains to block fetching from	nullable
cache_control	CacheControlEphemeral	Create a cache control breakpoint at this content block.	nullable
citations	RequestCitationsConfig	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	WebFetchUrlSources	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.

WebFetchToolResultErrorCodeenum

WebFetchUrlSourceAllobject

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"

WebFetchUrlSourceExceptobject

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

tools*	WebFetchUrlSourceToolReference[]
type*	const		"except"

WebFetchUrlSourceNoneobject

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"

WebFetchUrlSourceOnlyobject

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

tools*	WebFetchUrlSourceToolReference[]
type*	const		"only"

WebFetchUrlSourcesobject

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".

WebFetchUrlSourceToolReferenceobject

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"

WebSearchTool_20250305object

allowed_callers	AllowedCaller[]
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	CacheControlEphemeral	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	UserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

WebSearchTool_20260209object

allowed_callers	AllowedCaller[]
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	CacheControlEphemeral	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	UserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

WebSearchTool_20260318object

allowed_callers	AllowedCaller[]
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	CacheControlEphemeral	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	UserLocation	Parameters for the user's location. Used to provide more relevant search results.	nullable

WebSearchToolResultErrorCodeenum

Validate a payload

before you spend tokens

shell

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