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AI release notes
Anthropic's official release notes. Claude apps: the website, desktop and phone apps. Claude Code: Claude's coding assistant. Claude API: what developers use to build Claude into their own products.
Compiled by the Toolstash team · Updated
Claude API
The Claude Tag API is available in beta for Claude Enterprise organizations with the…
Its /v1/organizations/claude_tag/ endpoints read and change Claude Tag settings on Slack channels and Slack workspaces, show which settings apply in a channel and where each comes from, and attach Access bundles. Call it with an Admin API key that your primary owner creates in claude.ai with the read:claude_tag or write:claude_tag scope. It is not available to Claude Platform (Claude Console) organizations.
Claude API
We’ve launched Claude Models on Google Cloud, the Claude API operated by Anthropic and reached through your…
Google Cloud IAM controls access. Google Cloud Marketplace handles billing. Fast mode is available for Claude Opus 5.5 on Claude Models on Google Cloud (Anthropic managed).
Claude API
We’ve released API version 2026-10-21
Migrating to API version 2026-10-21 shows how to upgrade. We’ve released new versions of the client SDKs and the ant CLI that send API version 2026-10-21 by default: Python SDK 2.0.0, TypeScript SDK 1.0.0, C# SDK 13.0.0, Go SDK 2.0.0, Java SDK 3.0.0, PHP SDK 1.0.0, Ruby SDK 2.0.0, and ant CLI 2.0.0. The new SDK and CLI versions also have breaking changes that don’t depend on the API version, and they are licensed under Apache 2.0 instead of the MIT License. We’ve added the enforcement_status and enforcement_actions fields to user profiles, so you can see whether Anthropic has restricted or banned one of your end customers.
Claude API
Inference hooks are out of beta for Claude Enterprise organizations
We’ve launched user profiles, so you can tell Anthropic which of your end customers each API request is for. We’ve added organization webhooks to the Admin API, in beta with the webhooks-2026-10-07 beta header. Organization admins can now turn off web fetch for their organization on the Capabilities page of the Claude Console. In Claude Managed Agents, the web_fetch tool now follows your organization’s web fetch domain restrictions set on the Capabilities page of the Claude Console. In Claude Managed Agents, sessions follow your organization’s web search settings on the Capabilities page of the Claude Console: the Allow web search setting since October 6, and its web search domain restrictions since October 14.
Claude API
We’ve added capabilities.thinking.types.between_tools to the Models API
GET /v1/models and GET /v1/models/{model_id} now report whether each model accepts thinking: {type: "between_tools"}, which turns off up-front thinking. The Compliance API now returns the text each organization member saved as Instructions for Claude in claude.ai and as Global instructions in Cowork, in beta for Claude Enterprise organizations. Fast mode is out of research preview for Claude Opus 5.5, and you no longer need to request access. Fast mode for Claude Opus 5.5 is now available on Claude in Microsoft Foundry for deployments hosted on Azure.
Claude API
We’ve launched OpenTelemetry export in beta, so you can trace Messages API requests and Claude Managed…
The Claude SDK emits spans in Python, TypeScript, C#, Go, Java, PHP, and Ruby. To get spans from the API, add an OpenTelemetry destination in the Claude Console. Claude Managed Agents scheduled deployments are now available on Claude Platform on AWS.
Claude API
You can now let a Claude Managed Agents agent use dynamic workflows, in beta with the…
For work with many pieces, such as reviewing hundreds of documents, the agent can write a workflow. A workflow is a program that runs many agents in phases and combines their results. The server runs it in the background as a workflow run. To turn dynamic workflows on, set the agent’s multiagent field to {"type": "multiagent_20261001", "workflows": {"type": "enabled"}}. To guide the agent, tell it in its system prompt when to start a run. Follow each run through workflow_run.* events on the session’s event stream.
Claude API
The Compliance API chat endpoints now also return chats from the unified Claude experience, in beta for…
The Compliance API can now download Claude Docs documents as Word files, in beta.
Claude API
We’ve lowered the price of prompt cache reads on Claude Sonnet 5.5 from $0.20 USD to $0.10 USD per million…
Cache writes and all other prices are unchanged. Code written for Claude Haiku 4.5 can break on Claude Haiku 5.5. The Python and TypeScript SDKs now include classes, in beta, for the browser use tool and the computer use tool. Claude Max and Team plans now include monthly API credits. In Claude Managed Agents, a cloud environment with limited networking now also applies its allowed_hosts to the web_search and web_fetch tools. With limited networking, creating a session fails with a 400 error when an enabled web tool’s allowed_domains has an entry not within allowed_hosts. In Claude Managed Agents, the web_fetch tool now fetches only URLs that have already appeared in the session, for example in the text of a user message, in a web_search result, or in a page that web_fetch returned earlier.
Claude API
We’ve added capabilities.server_tools to the Models API
GET /v1/models and GET /v1/models/{model_id} now report whether each model accepts the web search and code execution tools. To check whether a model accepts the code execution tool, read capabilities.server_tools.code_execution. The top-level capabilities.code_execution reports whether code can call your request’s other tools.
Claude API
We’ve added capabilities.thinking.types.disabled to the Models API
GET /v1/models and GET /v1/models/{model_id} now report whether each model accepts thinking: {type: "disabled"}, which turns thinking off.
Claude API
We’ve added a line field to the Models API
GET /v1/models and GET /v1/models/{model_id} now return the model line each model belongs to. Claude Opus 4.5 and Claude Opus 4.6 both report opus, for example. Use line to group models without parsing their IDs. line is null for a model that belongs to no line. Dreams (research preview) now supports Claude Opus 5.5, Claude Fable 5.1, and Claude Sonnet 5.5.
Claude API
In Python SDK 1.10.0, TypeScript SDK 0.130.0, C# SDK 12.52.0, Go SDK 1.77.0, Java SDK 2.67.0, PHP SDK…
These releases also keep client.beta.organization and ant beta:organization. We announced the deprecation of the Claude Sonnet 4.5 model (claude-sonnet-4-5-20250929), with retirement on the Claude API scheduled for November 30, 2026.
Claude API
Code written for Claude Sonnet 5 can break on Claude Sonnet 5.5 in five ways
To turn off up-front thinking, send thinking: {"type": "between_tools"} instead of "disabled", at high effort or below. Forced tool use (tool_choice types any and tool) returns a 400 error. Thinking blocks are tied to the model and the conversation. On the Claude API and Google Cloud, the earlier computer_20251124 computer use tool isn’t accepted. The advisor tool rejects Claude Opus 4.8, Claude Opus 4.7, and Claude Sonnet 5 as advisors. For model-specific prompting patterns, see Prompting Claude Sonnet 5.5. Thinking blocks that Claude Sonnet 5.5 produces work only in the account that produced them, or in an account linked to it.
Claude API
We’re resuming billing for refusals that arrive before any output when stop_details.category is "bio",…
Mid-stream refusals were already billed. Refusals billed under this change are charged like any other request, at the rates of the model that ran it. Refusals before any output in other categories are still not billed, and fallback credit is unchanged. This change applies on all platforms. The Compliance API local session endpoints are out of beta for Claude for Microsoft 365 sessions in Excel, PowerPoint, Word, and Outlook (product_surface values beginning with office_agents). The Compliance API Activity Feed no longer returns file names, project document names, or artifact titles.
Claude API
Cache diagnostics is out of beta on the Claude API and no longer requires the cache-diagnosis-2026-04-07…
Include the diagnostics object on a Messages request to opt in; requests that still send the header work as before. Responses from POST /v1/messages now always include the diagnostics field, which is null when the request did not include the diagnostics object.
Claude API
On Claude Opus 5.5, thinking can’t be disabled: thinking: {"type": "disabled"} and thinking: {"type":…
Omit the thinking field and control thinking depth with the effort parameter. tool_choice types any and tool also return a 400 error, as on Claude Fable 5.1; use auto with strict tool use. On the Claude API and Google Cloud, computer use on this model requires the computer_toolset_20260801 toolset and the earlier computer_20251124 tool returns a 400 error; on Amazon Bedrock, computer_20251124 keeps working. Fast mode (research preview) is available for Claude Opus 5.5 on the Claude API. Tools can now be defined inside a mid-conversation system message, in beta on the Claude API with the inline-tools-2026-09-15 beta header.
Claude API
For cache diagnostics, a response to a request that sends the cache-diagnosis-2026-04-07 beta header now…
The field is null when the request did not include the diagnostics object. Previously the field was omitted in that case. The Compliance API local session endpoints now also return transcripts of Claude in Chrome sessions (product_surface value claude_in_chrome), in beta for Claude Enterprise organizations, with your existing Compliance Access Key and the read:compliance_user_data scope.
Claude API
The Messages API can now compact a conversation on demand on the Claude API, in beta with the…
Send the top-level compaction parameter, and the API returns a signed compaction block that summarizes the messages you sent. On later requests, send that block first, in place of those messages. You choose when to compact, the request can run in the background, and you can keep recent turns word for word after the summary. On models with preserved thinking, the thinking in those kept turns can stay valid. With the thinking-binding-controls-2026-08-01 beta header, the input_transformations response field gains a second entry type, thinking_mismatch_allowed.
Claude API
Claude Managed Agents permission policies now include auto: the server evaluates each agent or MCP tool call…
Version 1.32.0 of the ant CLI adds ant beta:sessions connect, which attaches your terminal to a Claude Managed Agents session.
Claude API
For cache diagnostics, the API now stores a request’s fingerprint only when the request includes the…
A request that sends only the cache-diagnosis-2026-04-07 beta header is still accepted, but no fingerprint is stored. A later turn that points previous_message_id at it reports previous_message_not_found. Include diagnostics on every turn, with "previous_message_id": null on the first.
Claude API
Version 1.30.0 of the ant CLI adds ant apply, which creates and updates agents, environments, skills, memory…
Describe each resource in a file, run ant apply, and approve the plan it prints. Commit the claude-lock.json lockfile it writes so that later runs, on your machine or in CI, update the same resources instead of creating new ones. Per-message effort changes, in beta, are also available on Google Cloud for Claude Fable 5.1, Claude Mythos 5.1, and Claude Opus 5, with the same mid-conversation-output-config-2026-07-01 beta header.
Claude API
Prompt cache reads on Claude Fable 5.1 and Claude Mythos 5.1 cost $0.25 USD per million tokens: 0.025x the…
Cache writes are unchanged. On Claude Fable 5.1 and Claude Mythos 5.1, tool_choice types any and tool aren’t supported and return a 400 error. auto and none are unchanged. Thinking blocks produced by Claude Fable 5.1 and Claude Mythos 5.1 are preserved only for the model that produced them or a newer one: earlier models can’t read them, and the API drops one replayed to an earlier model. Per-message effort changes are in beta on Claude Fable 5.1, Claude Mythos 5.1, and Claude Opus 5 on the Claude API. Turn-scoped system messages are in beta (mid-conversation-system-clear-at-2026-08-21 header). thinking.display accepts a third value, "updates", in beta (thinking-display-updates-2026-08-18 header). Text generated by Claude Fable 5.1 and Claude Mythos 5.1 carries Anthropic’s text watermark, and supported image, video, and audio files that Claude produces through the code execution tool carry C2PA Content Credentials when you retrieve them through the Files API on the Claude API. Like Claude Fable 5, both models require 30-day data retention and aren’t available under zero data retention unless expressly authorized by Anthropic. The guides for the Claude Enterprise endpoints of the Admin API (user management and spend limits), the Claude Enterprise Analytics API, and the Compliance API now show the anthropic-version header; send it on every request to these endpoints, as in the rest of the Claude API.
Claude API
In Python SDK 1.2.0, TypeScript SDK 0.122.0, Go SDK 1.68.0, Java SDK 2.59.0, Ruby SDK 1.67.0, and C# SDK…
With this change, client.beta.skills.delete() deletes a Skill together with all of its versions, and the beta Messages type BetaSkill (the container Skill reference) is renamed BetaContainerSkill. Requests that still send the beta headers keep receiving the beta shapes. You can now create personal keys and service account keys in the Claude Console.
Claude API
The Compliance API session endpoints are out of beta for Cowork and Claude Code sessions
The Compliance API local session endpoints now also return transcripts of Claude Science sessions (product_surface value claude_science) and Claude for Microsoft 365 sessions in Excel, PowerPoint, Word, and Outlook (product_surface values beginning with office_agents), in beta for Claude Enterprise organizations, with your existing Compliance Access Key and the read:compliance_user_data scope. The Admin API is now available in the ant CLI and the Python, TypeScript, C#, Go, Java, PHP, and Ruby SDKs under client.beta.organization.
Claude API
We’ve released v1.0 of the Python SDK
The SDK’s HTTP layer moves from httpx to httpx2, a maintained, API-compatible fork: build custom http_client, Timeout, and transport objects from httpx2 (the DefaultHttpxClient helpers are unchanged), and call httpx2.alias_httpx() at startup if you rely on tracing or mocking libraries that patch httpx. v1.0 requires Python 3.10 or later and removes long-deprecated surface, including the legacy Text Completions API, the temperature, top_p, and top_k parameters on Messages methods, and the tool runner’s client-side compaction_control. On the async client,.with_raw_response results now need await response.parse(), and AnthropicBedrock now raises an error when no AWS region is configured instead of defaulting to us-east-1. The computer use and browser use toolsets (computer_toolset_20260801 and browser_toolset_20260801) are now available on Google Cloud for Claude Fable 5, Claude Mythos 5, Claude Opus 5, Claude Sonnet 5, and Claude Opus 4.8.
Claude API
The computer use tool is out of beta on the Claude API as the computer_toolset_20260801 toolset: no beta…
Earlier beta versions remain available. Upgrading an existing integration changes the request shape and tool handling; see Migrate from computer_20251124. We’ve launched the browser use tool (browser_toolset_20260801), a client toolset for driving a browser that your application hosts. Both toolsets are available for Claude Fable 5, Claude Mythos 5, Claude Opus 5, Claude Sonnet 5, and Claude Opus 4.8 on the Claude API. The Files API is out of beta on the Claude API. Agent Skills and the Skills API (/v1/skills) are out of beta on the Claude API. The Admin API user-management endpoints for Claude Enterprise (claude.ai) organizations (members, invites, groups, and custom roles) are out of beta. You can now restrict which sites a Claude Managed Agents agent’s web_search and web_fetch tools can reach. Claude Managed Agents sessions that run in a self-hosted sandbox can now attach memory stores. The session viewer in the Claude Console has been redesigned with a timeline minimap, a transcript grouped by model request, and an Inspector panel for session details and cost, raw events, per-tool statistics, mounted resources, and per-thread activity.
Claude API
Workbench is now playground in the Claude Console
Playground supports every Messages API parameter and includes templates that demonstrate API features such as code execution and web search. It shows the full SDK request and the API response for each run, to help you understand the API and build with it. For more, see the Claude Help Center or try it at platform.claude.com/playground.
Claude API
The Compliance API now returns transcripts of Cowork and Claude Code sessions that run on your users’…
GET /v1/compliance/apps/sessions/local lists sessions across your organization, GET /v1/compliance/apps/sessions/local/{session_id} retrieves one session’s metadata, and GET /v1/compliance/apps/sessions/local/{session_id}/messages returns its transcript, all with your existing Compliance Access Key and the read:compliance_user_data scope. We’ve added the anthropic-workspace-id response header to the Claude API.
Claude API
The introductory pricing for Claude Sonnet 5 is now the standard price: the previously scheduled increase to…