--- title: "Count tokens in a Message" method: POST path: "/v1/messages/count_tokens?beta=true" --- # Count tokens in a Message `POST /v1/messages/count_tokens?beta=true` Count the number of tokens in a Message. The Token Count API can be used to count the number of tokens in a Message, including tools, images, and documents, without creating it. Learn more about token counting in our [user guide](https://platform.claude.com/docs/en/build-with-claude/token-counting) ## Headers - `anthropic-beta` string — Optional header to specify the beta version(s) you want to use. To use multiple betas, use a comma separated list like `beta1,beta2` or specify the header multiple times for each beta. - `anthropic-version` string — The version of the Claude API you want to use. Read more about versioning and our version history [here](https://platform.claude.com/docs/en/api/versioning). - `anthropic-user-profile-id` string — The user profile ID to attribute this request to. Use when acting on behalf of a party other than your organization. Requires the `user-profiles` beta header. ## Request body - BetaCountMessageTokensParams - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `context_management` BetaContextManagementConfig - `edits` union[] — List of context management edits to apply - union - BetaClearToolUses20250919 - `clear_at_least` BetaInputTokensClearAtLeast - `type` 'input_tokens', required - `value` integer, required - `clear_tool_inputs` union — Whether to clear all tool inputs (bool) or specific tool inputs to clear (list) - boolean - string[] - `exclude_tools` string[], nullable — Tool names whose uses are preserved from clearing - `keep` BetaToolUsesKeep - `type` 'tool_uses', required - `value` integer, required - `trigger` union — Condition that triggers the context management strategy - BetaInputTokensTrigger - … - BetaToolUsesTrigger - … - `type` 'clear_tool_uses_20250919', required - BetaClearThinking20251015 - `keep` union — Number of most recent assistant turns to keep thinking blocks for. Older turns will have their thinking blocks removed. - union - … - 'all' - `type` 'clear_thinking_20251015', required - BetaCompact20260112 — Automatically compact older context when reaching the configured trigger threshold. - `instructions` string, nullable — Additional instructions for summarization. - `pause_after_compaction` boolean — Whether to pause after compaction and return the compaction block to the user. - `trigger` BetaInputTokensTrigger - `type` 'input_tokens', required - `value` integer, required - `type` 'compact_20260112', required - `mcp_servers` BetaRequestMCPServerURLDefinition[] — MCP servers to be utilized in this request - `authorization_token` string, nullable - `name` string, required - `tool_configuration` BetaRequestMCPServerToolConfiguration - `allowed_tools` string[], nullable - `enabled` boolean, nullable - `type` 'url', required - `url` string, required - `messages` BetaInputMessage[], required — Input messages. Our models are trained to operate on alternating `user` and `assistant` conversational turns. When creating a new `Message`, you specify the prior conversational turns with the `messages` parameter, and the model then generates the next `Message` in the conversation. Consecutive `user` or `assistant` turns in your request will be combined into a single turn. Each input message must be an object with a `role` and `content`. You can specify a single `user`-role message, or you can include multiple `user` and `assistant` messages. If the final message uses the `assistant` role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response. Example with a single `user` message: ```json [{"role": "user", "content": "Hello, Claude"}] ``` Example with multiple conversational turns: ```json [ {"role": "user", "content": "Hello there."}, {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"}, {"role": "user", "content": "Can you explain LLMs in plain English?"}, ] ``` Example with a partially-filled response from Claude: ```json [ {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"}, {"role": "assistant", "content": "The best answer is ("}, ] ``` Each input message `content` may be either a single `string` or an array of content blocks, where each block has a specific `type`. Using a `string` for `content` is shorthand for an array of one content block of type `"text"`. The following input messages are equivalent: ```json {"role": "user", "content": "Hello, Claude"} ``` ```json {"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]} ``` See [input examples](https://platform.claude.com/docs/en/build-with-claude/working-with-messages). Note that if you want to include a [system prompt](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices#give-claude-a-role), you can use the top-level `system` parameter — there is no `"system"` role for input messages in the Messages API. There is a limit of 100,000 messages in a single request. - `content` union, required - string - BetaInputContentBlock[] - union - object - `cache_control` BetaCacheControlEphemeral - … - `citations` union[], nullable - … - `text` string, required - `type` 'text', required - object - `cache_control` BetaCacheControlEphemeral - … - `source` union, required - … - `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 object is equivalent to omitting the field. - … - `type` 'image', required - object - `cache_control` BetaCacheControlEphemeral - … - `citations` BetaRequestCitationsConfig - … - `context` string, nullable - `source` union, required - … - `title` string, nullable - `type` 'document', required - object - `cache_control` BetaCacheControlEphemeral - … - `citations` BetaRequestCitationsConfig - … - `content` BetaRequestTextBlock[], required - … - `source` string, required - `title` string, required - `type` 'search_result', required - object - `signature` string, required — 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 blocks must be passed back unmodified and in their original order; a modified block results in a 400 `invalid_request_error`. - `thinking` string, required — The `thinking` text of this block as returned by the API. - `type` 'thinking', required - object - `data` string, required — 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` 'redacted_thinking', required - object - `cache_control` BetaCacheControlEphemeral - … - `caller` union - … - `id` string, required - `input` object, required - `name` string, required - `toolset_name` string, nullable — For a toolset member tool_use, the toolset family this member belongs to. - `type` 'tool_use', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union - … - `is_error` boolean - `tool_use_id` string, required - `toolset_name` string, nullable — For a toolset member tool_result, the toolset family of the paired tool_use. - `type` 'tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `caller` union - … - `id` string, required - `input` object, required - `name` 'advisor' | 'web_search' | 'web_fetch' | 'code_execution' | 'bash_code_execution' | 'text_editor_code_execution' | 'tool_search_tool_regex' | 'tool_search_tool_bm25', required - `type` 'server_tool_use', required - object - `cache_control` BetaCacheControlEphemeral - … - `caller` union - … - `content` union, required - … - `tool_use_id` string, required - `type` 'web_search_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `caller` union - … - `content` union, required - … - `tool_use_id` string, required - `type` 'web_fetch_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union, required - … - `tool_use_id` string, required - `type` 'advisor_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union, required - … - `tool_use_id` string, required - `type` 'code_execution_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union, required - … - `tool_use_id` string, required - `type` 'bash_code_execution_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union, required - … - `tool_use_id` string, required - `type` 'text_editor_code_execution_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union, required - … - `tool_use_id` string, required - `type` 'tool_search_tool_result', required - object - `cache_control` BetaCacheControlEphemeral - … - `id` string, required - `input` object, required - `name` string, required - `server_name` string, required — The name of the MCP server - `type` 'mcp_tool_use', required - object - `cache_control` BetaCacheControlEphemeral - … - `content` union - … - `is_error` boolean - `tool_use_id` string, required - `type` 'mcp_tool_result', required - object — 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 - … - `file_id` string, required - `type` 'container_upload', required - object — A compaction block containing summary of previous context. Users should round-trip these blocks from responses to subsequent requests to maintain context across compaction boundaries. When content is None, the block represents a failed compaction. The server treats these as no-ops. Empty string content is not allowed. - `cache_control` BetaCacheControlEphemeral - … - `content` string, nullable — Summary of previously compacted content, or null if compaction failed - `encrypted_content` string, nullable — Opaque metadata from prior compaction, to be round-tripped verbatim - `type` 'compaction', required - object — Mid-conversation directive to surface a declared tool. ``tool`` references a tool (or MCP toolset) by name from the request's ``tools``; it is offered to the model from this point in the conversation onward. - `cache_control` BetaCacheControlEphemeral - … - `tool` union, required - … - `type` 'tool_addition', required - object — Mid-conversation directive to withdraw a tool. ``tool`` references a tool (or MCP toolset) by name from the request's ``tools``; it is no longer offered to the model from this point in the conversation onward. - `cache_control` BetaCacheControlEphemeral - … - `tool` union, required - … - `type` 'tool_removal', required - object — A `fallback` block echoed back from a prior response. Accepted in `messages[].content` and not rendered into the prompt; not validated against the request's `fallbacks` chain or top-level `model`. Echo the assistant turn back verbatim, including this block in its original position. The block marks the boundary between content produced before and after a fallback hop, and the server relies on that boundary to validate the turn: when thinking runs flank the boundary, omitting the block merges them into one span the server cannot validate (the request is rejected), and moving it into the middle of a single run is likewise rejected; between non-thinking blocks the block's placement has no validation effect. - `from` BetaRequestFallbackHopInfo, required — Identifies one hop of a fallback transition. - … - `to` BetaRequestFallbackHopInfo, required — Identifies one hop of a fallback transition. - … - `trigger` unknown - `type` 'fallback', required - `role` 'user' | 'assistant' | 'system', required - `model` union, required — The model that will complete your prompt. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - string - 'claude-sonnet-5' — High-performance model for coding and agents - 'claude-fable-5' — Next generation of intelligence for the hardest knowledge work and coding problems - 'claude-mythos-5' — Most capable model for cybersecurity and biology research - 'claude-opus-5' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-8' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-7' — Powerful intelligence for long-running agents and coding - 'claude-mythos-preview' — New class of intelligence, strongest in coding and cybersecurity - 'claude-opus-4-6' — Powerful intelligence for long-running agents and coding - 'claude-sonnet-4-6' — Best combination of speed and intelligence - 'claude-haiku-4-5' — Fastest model with near-frontier intelligence - 'claude-haiku-4-5-20251001' — Fastest model with near-frontier intelligence - 'claude-opus-4-5' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-5-20251101' — Powerful intelligence for long-running agents and coding - 'claude-sonnet-4-5' — High-performance model for agents and coding - 'claude-sonnet-4-5-20250929' — High-performance model for agents and coding - `output_config` BetaOutputConfig - `effort` 'low' | 'medium' | 'high' | 'xhigh' | 'max' — All possible effort levels. - `format` BetaJsonOutputFormat - `schema` object, required — The JSON schema of the format - `type` 'json_schema', required - `task_budget` BetaTokenTaskBudget — User-configurable total token budget across contexts. - `remaining` integer, nullable — Remaining tokens in the budget. Use this to track usage across contexts when implementing compaction client-side. Defaults to total if not provided. - `total` integer, required — Total token budget across all contexts in the session. - `type` 'tokens', required — The budget type. Currently only 'tokens' is supported. - `output_format` BetaJsonOutputFormat - `schema` object, required — The JSON schema of the format - `type` 'json_schema', required - `speed` 'standard' | 'fast' — Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time. - `system` union — System prompt. A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our [guide to system prompts](https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices#give-claude-a-role). - string - BetaRequestTextBlock[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `citations` union[], nullable - union - BetaRequestCharLocationCitation - `cited_text` string, required - `document_index` integer, required - `document_title` string, nullable, required - `end_char_index` integer, required - `start_char_index` integer, required - `type` 'char_location', required - BetaRequestPageLocationCitation - `cited_text` string, required - `document_index` integer, required - `document_title` string, nullable, required - `end_page_number` integer, required - `start_page_number` integer, required - `type` 'page_location', required - BetaRequestContentBlockLocationCitation - `cited_text` string, required — The full text of the cited block range, concatenated. Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns. - `document_index` integer, required - `document_title` string, nullable, required - `end_block_index` integer, required — Exclusive 0-based end index of the cited block range in the source's `content` array. Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`. - `start_block_index` integer, required — 0-based index of the first cited block in the source's `content` array. - `type` 'content_block_location', required - BetaRequestWebSearchResultLocationCitation - `cited_text` string, required - `encrypted_index` string, required - `title` string, nullable, required - `type` 'web_search_result_location', required - `url` string, required - BetaRequestSearchResultLocationCitation - `cited_text` string, required — The full text of the cited block range, concatenated. Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns. - `end_block_index` integer, required — Exclusive 0-based end index of the cited block range in the source's `content` array. Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`. - `search_result_index` integer, required — 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. Counted separately from `document_index`; server-side web search results are not included in this count. - `source` string, required - `start_block_index` integer, required — 0-based index of the first cited block in the source's `content` array. - `title` string, nullable, required - `type` 'search_result_location', required - `text` string, required - `type` 'text', required - `thinking` union — Configuration for enabling Claude's extended thinking. When enabled, responses include `thinking` content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your `max_tokens` limit. See [extended thinking](https://platform.claude.com/docs/en/build-with-claude/extended-thinking) for details. - BetaThinkingConfigEnabled - `budget_tokens` integer, required — 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. Must be ≥1024 and less than `max_tokens`. See [extended thinking](https://platform.claude.com/docs/en/build-with-claude/extended-thinking) for details. - `display` 'summarized' | 'omitted' - `type` 'enabled', required - BetaThinkingConfigDisabled - `type` 'disabled', required - BetaThinkingConfigAdaptive - `display` 'summarized' | 'omitted' - `type` 'adaptive', required - `tool_choice` union — 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. - BetaToolChoiceAuto — The model will automatically decide whether to use tools. - `disable_parallel_tool_use` boolean — Whether to disable parallel tool use. Defaults to `false`. If set to `true`, the model will output at most one tool use. - `type` 'auto', required - BetaToolChoiceAny — The model will use any available tools. - `disable_parallel_tool_use` boolean — Whether to disable parallel tool use. Defaults to `false`. If set to `true`, the model will output exactly one tool use. - `type` 'any', required - BetaToolChoiceTool — The model will use the specified tool with `tool_choice.name`. - `disable_parallel_tool_use` boolean — Whether to disable parallel tool use. Defaults to `false`. If set to `true`, the model will output exactly one tool use. - `name` string, required — The name of the tool to use. - `type` 'tool', required - BetaToolChoiceNone — The model will not be allowed to use tools. - `type` 'none', required - `tools` union[] — Definitions of tools that the model may use. If you include `tools` in your API request, the model may return `tool_use` content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using `tool_result` content blocks. There are two types of tools: **client tools** and **server tools**. The behavior described below applies to client tools. For [server tools](https://platform.claude.com/docs/en/agents-and-tools/tool-use/server-tools), see their individual documentation as each has its own behavior (e.g., the [web search tool](https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-search-tool)). Each tool definition includes: * `name`: Name of the tool. * `description`: Optional, but strongly-recommended description of the tool. * `input_schema`: [JSON schema](https://json-schema.org/draft/2020-12) for the tool `input` shape that the model will produce in `tool_use` output content blocks. For example, if you defined `tools` as: ```json [ { "name": "get_stock_price", "description": "Get the current stock price for a given ticker symbol.", "input_schema": { "type": "object", "properties": { "ticker": { "type": "string", "description": "The stock ticker symbol, e.g. AAPL for Apple Inc." } }, "required": ["ticker"] } } ] ``` And then asked the model "What's the S&P 500 at today?", the model might produce `tool_use` content blocks in the response like this: ```json [ { "type": "tool_use", "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV", "name": "get_stock_price", "input": { "ticker": "^GSPC" } } ] ``` You might then run your `get_stock_price` tool with `{"ticker": "^GSPC"}` as an input, and return the following back to the model in a subsequent `user` message: ```json [ { "type": "tool_result", "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV", "content": "259.75 USD" } ] ``` Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output. See our [guide](https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview) for more details. - union - BetaTool - `type` 'custom', nullable - `description` string — Description of what this tool does. Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema. - `name` string, required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `input_schema` BetaInputSchema, required - `properties` object, nullable - `required` string[], nullable - `type` 'object', required - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `eager_input_streaming` boolean, nullable — 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. - `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[] - BetaBashTool20241022 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'bash', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'bash_20241022', required - BetaBashTool20250124 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'bash', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'bash_20250124', required - BetaCodeExecutionTool20250522 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'code_execution', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'code_execution_20250522', required - BetaCodeExecutionTool20250825 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'code_execution', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'code_execution_20250825', required - BetaCodeExecutionTool20260120 — Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint). - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'code_execution', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'code_execution_20260120', required - BetaCodeExecutionTool20260521 — Code execution tool with REPL state persistence. - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'code_execution', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'code_execution_20260521', required - BetaBrowserToolset20260801 — 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. - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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 absent. Unknown keys are rejected: the field set is this toolset version's complete member set. - `close_tab` BetaBrowserCloseTabConfig — ``close_tab``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `double_click` BetaBrowserDoubleClickConfig — ``double_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `file_upload` BetaBrowserFileUploadConfig — ``file_upload``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `find` BetaBrowserFindConfig — ``find``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `form_input` BetaBrowserFormInputConfig — ``form_input``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `get_page_text` BetaBrowserGetPageTextConfig — ``get_page_text``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `hold_key` BetaBrowserHoldKeyConfig — ``hold_key``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `hover` BetaBrowserHoverConfig — ``hover``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `javascript_exec` BetaBrowserJavascriptExecConfig — ``javascript_exec``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `key` BetaBrowserKeyConfig — ``key``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_click` BetaBrowserLeftClickConfig — ``left_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_click_drag` BetaBrowserLeftClickDragConfig — ``left_click_drag``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_mouse_down` BetaBrowserLeftMouseDownConfig — ``left_mouse_down``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_mouse_up` BetaBrowserLeftMouseUpConfig — ``left_mouse_up``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `list_tabs` BetaBrowserListTabsConfig — ``list_tabs``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `middle_click` BetaBrowserMiddleClickConfig — ``middle_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `mouse_move` BetaBrowserMouseMoveConfig — ``mouse_move``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `navigate` BetaBrowserNavigateConfig — ``navigate``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `new_tab` BetaBrowserNewTabConfig — ``new_tab``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `read_console` BetaBrowserReadConsoleConfig — ``read_console``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `read_network` BetaBrowserReadNetworkConfig — ``read_network``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `read_page` BetaBrowserReadPageConfig — ``read_page``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `right_click` BetaBrowserRightClickConfig — ``right_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `screenshot` BetaBrowserScreenshotConfig — ``screenshot``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `scroll` BetaBrowserScrollConfig — ``scroll``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `scroll_to` BetaBrowserScrollToConfig — ``scroll_to``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `switch_tab` BetaBrowserSwitchTabConfig — ``switch_tab``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `triple_click` BetaBrowserTripleClickConfig — ``triple_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `type` BetaBrowserTypeConfig — ``type``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `wait` BetaBrowserWaitConfig — ``wait``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `zoom` BetaBrowserZoomConfig — ``zoom``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `type` 'browser_toolset_20260801', required - BetaComputerUseTool20241022 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, required — The height of the display in pixels. - `display_number` integer, nullable — The X11 display number (e.g. 0, 1) for the display. - `display_width_px` integer, required — The width of the display in pixels. - `input_examples` object[] - `name` 'computer', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'computer_20241022', required - BetaMemoryTool20250818 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'memory', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'memory_20250818', required - BetaComputerUseTool20250124 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, required — The height of the display in pixels. - `display_number` integer, nullable — The X11 display number (e.g. 0, 1) for the display. - `display_width_px` integer, required — The width of the display in pixels. - `input_examples` object[] - `name` 'computer', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'computer_20250124', required - BetaTextEditor20241022 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'str_replace_editor', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'text_editor_20241022', required - BetaComputerUseTool20251124 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, required — The height of the display in pixels. - `display_number` integer, nullable — The X11 display number (e.g. 0, 1) for the display. - `display_width_px` integer, required — The width of the display in pixels. - `enable_zoom` boolean — Whether to enable an action to take a zoomed-in screenshot of the screen. - `input_examples` object[] - `name` 'computer', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'computer_20251124', required - BetaComputerToolset20260801 — 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 included. The single-tool options ``display_number`` and ``enable_zoom`` are not fields of a toolset entry — it carries only ``type``, ``configs``, and ``cache_control``; zoom is controlled via ``configs.zoom.enabled``. - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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 absent. Unknown keys are rejected: the field set is this toolset version's complete member set. - `cursor_position` BetaComputerCursorPositionConfig — ``cursor_position``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `double_click` BetaComputerDoubleClickConfig — ``double_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `hold_key` BetaComputerHoldKeyConfig — ``hold_key``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `key` BetaComputerKeyConfig — ``key``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_click` BetaComputerLeftClickConfig — ``left_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_click_drag` BetaComputerLeftClickDragConfig — ``left_click_drag``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_mouse_down` BetaComputerLeftMouseDownConfig — ``left_mouse_down``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `left_mouse_up` BetaComputerLeftMouseUpConfig — ``left_mouse_up``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `middle_click` BetaComputerMiddleClickConfig — ``middle_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `mouse_move` BetaComputerMouseMoveConfig — ``mouse_move``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `right_click` BetaComputerRightClickConfig — ``right_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `screenshot` BetaComputerScreenshotConfig — ``screenshot``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `scroll` BetaComputerScrollConfig — ``scroll``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `triple_click` BetaComputerTripleClickConfig — ``triple_click``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `type` BetaComputerTypeConfig — ``type``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `wait` BetaComputerWaitConfig — ``wait``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `zoom` BetaComputerZoomConfig — ``zoom``'s config overrides. - `defer_loading` boolean, nullable — Defer loading for this member. Must resolve to the same value on every enabled member of the toolset. - `enabled` boolean, nullable — 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. - `type` 'computer_toolset_20260801', required - BetaTextEditor20250124 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'str_replace_editor', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'text_editor_20250124', required - BetaTextEditor20250429 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'str_replace_based_edit_tool', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'text_editor_20250429', required - BetaTextEditor20250728 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, nullable — Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file. - `name` 'str_replace_based_edit_tool', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'text_editor_20250728', required - BetaWebSearchTool20250305 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`. - `blocked_domains` string[], nullable — If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`. - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_search', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_search_20250305', required - `user_location` BetaUserLocation - `city` string, nullable — The city of the user. - `country` string, nullable — The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user. - `region` string, nullable — The region of the user. - `timezone` string, nullable — The [IANA timezone](https://nodatime.org/TimeZones) of the user. - `type` 'approximate', required - BetaWebFetchTool20250910 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — List of domains to allow fetching from - `blocked_domains` string[], nullable — List of domains to block fetching from - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `citations` BetaRequestCitationsConfig - `enabled` boolean - `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, nullable — 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. - `max_uses` integer, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_fetch', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_fetch_20250910', required - BetaWebSearchTool20260209 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`. - `blocked_domains` string[], nullable — If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`. - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_search', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_search_20260209', required - `user_location` BetaUserLocation - `city` string, nullable — The city of the user. - `country` string, nullable — The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user. - `region` string, nullable — The region of the user. - `timezone` string, nullable — The [IANA timezone](https://nodatime.org/TimeZones) of the user. - `type` 'approximate', required - BetaWebFetchTool20260209 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — List of domains to allow fetching from - `blocked_domains` string[], nullable — List of domains to block fetching from - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `citations` BetaRequestCitationsConfig - `enabled` boolean - `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, nullable — 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. - `max_uses` integer, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_fetch', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_fetch_20260209', required - BetaWebFetchTool20260309 — Web fetch tool with use_cache parameter for bypassing cached content. - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — List of domains to allow fetching from - `blocked_domains` string[], nullable — List of domains to block fetching from - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `citations` BetaRequestCitationsConfig - `enabled` boolean - `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, nullable — 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. - `max_uses` integer, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_fetch', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_fetch_20260309', required - `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. - BetaWebSearchTool20260318 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`. - `blocked_domains` string[], nullable — If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`. - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_search', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `response_inclusion` 'full' | 'excluded' — 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. Results from direct calls, or from code_execution calls that paused before completing, are always returned in full so they can be sent back on the next turn. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_search_20260318', required - `user_location` BetaUserLocation - `city` string, nullable — The city of the user. - `country` string, nullable — The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user. - `region` string, nullable — The region of the user. - `timezone` string, nullable — The [IANA timezone](https://nodatime.org/TimeZones) of the user. - `type` 'approximate', required - BetaWebFetchTool20260318 - `allowed_callers` BetaAllowedCaller[] - `allowed_domains` string[], nullable — List of domains to allow fetching from - `blocked_domains` string[], nullable — List of domains to block fetching from - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `citations` BetaRequestCitationsConfig - `enabled` boolean - `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, nullable — 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. - `max_uses` integer, nullable — Maximum number of times the tool can be used in the API request. - `name` 'web_fetch', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `response_inclusion` 'full' | 'excluded' — 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. Results from direct calls, or from code_execution calls that paused before completing, are always returned in full so they can be sent back on the next turn. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'web_fetch_20260318', required - `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. - BetaAdvisorTool20260301 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `caching` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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, nullable — 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 server also emits a remaining-tokens budget block in the advisor's prompt so the advisor self-shapes toward the cap. When omitted, the advisor model's default output cap applies and no budget block is emitted. - `max_uses` integer, nullable — Maximum number of times the tool can be used in the API request. - `model` union, required — The model that will complete your prompt. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - string - 'claude-sonnet-5' — High-performance model for coding and agents - 'claude-fable-5' — Next generation of intelligence for the hardest knowledge work and coding problems - 'claude-mythos-5' — Most capable model for cybersecurity and biology research - 'claude-opus-5' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-8' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-7' — Powerful intelligence for long-running agents and coding - 'claude-mythos-preview' — New class of intelligence, strongest in coding and cybersecurity - 'claude-opus-4-6' — Powerful intelligence for long-running agents and coding - 'claude-sonnet-4-6' — Best combination of speed and intelligence - 'claude-haiku-4-5' — Fastest model with near-frontier intelligence - 'claude-haiku-4-5-20251001' — Fastest model with near-frontier intelligence - 'claude-opus-4-5' — Powerful intelligence for long-running agents and coding - 'claude-opus-4-5-20251101' — Powerful intelligence for long-running agents and coding - 'claude-sonnet-4-5' — High-performance model for agents and coding - 'claude-sonnet-4-5-20250929' — High-performance model for agents and coding - `name` 'advisor', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'advisor_20260301', required - BetaToolSearchToolBM2520251119 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'tool_search_tool_bm25', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'tool_search_tool_bm25_20251119' | 'tool_search_tool_bm25', required - BetaToolSearchToolRegex20251119 - `allowed_callers` BetaAllowedCaller[] - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `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` 'tool_search_tool_regex', required — Name of the tool. This is how the tool will be called by the model and in `tool_use` blocks. - `strict` boolean — When true, guarantees schema validation on tool names and inputs - `type` 'tool_search_tool_regex_20251119' | 'tool_search_tool_regex', required - BetaMCPToolset — Configuration for a group of tools from an MCP server. Allows configuring enabled status and defer_loading for all tools from an MCP server, with optional per-tool overrides. - `cache_control` BetaCacheControlEphemeral - `ttl` '5m' | '1h' — The time-to-live for the cache control breakpoint. This may be one the following values: - `5m`: 5 minutes - `1h`: 1 hour Defaults to `5m`. See [prompt caching pricing](https://platform.claude.com/docs/en/build-with-claude/prompt-caching) for details. - `type` 'ephemeral', required - `configs` object, nullable — Configuration overrides for specific tools, keyed by tool name - `default_config` BetaMCPToolDefaultConfig — Default configuration for tools in an MCP toolset. - `defer_loading` boolean - `enabled` boolean - `mcp_server_name` string, required — Name of the MCP server to configure tools for - `type` 'mcp_toolset', required ## Response `200` Successful Response - BetaCountMessageTokensResponse - `context_management` BetaContextManagementResponse, required - `original_input_tokens` integer, required — The original token count before context management was applied - `input_tokens` integer, required — The total number of tokens across the provided list of messages, system prompt, and tools. ## Other responses - `4XX` — Error response. See our [errors documentation](https://platform.claude.com/docs/en/api/errors) for more details. --- [API](https://skmtc.net/anthropics/apis/anthropic-api.md) · [All operations](https://skmtc.net/anthropics/apis/anthropic-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/anthropics/anthropic-api/revisions/0042750ea1ee/schema)