Claude Platform

The fallbacks parameter now supports a "default" mode that applies Anthropic's recommended fallback models by refusal category. Server-side fallback is in beta and requires the server-side-fallback-2026-07-01 beta header.

Fast mode is removed for Claude Opus 4.7 — requests with speed: "fast" now return an error. Opus 4.7 remains available at standard speed; migrate to Opus 5 or Opus 4.8 to continue using fast mode.

Claude Opus 5 is now available with a 1M token context window, 128k max output tokens, and thinking enabled by default. Disabling thinking is only allowed at effort high or below, and effort becomes the primary steering control with a full low-to-max ladder.

Mid-conversation tool changes are now in beta on Claude Fable 5, Mythos 5, Opus 4.8, and Opus 5, allowing tools to be added or removed between turns while preserving the prompt cache. Include the mid-conversation-tool-changes-2026-07-01 beta header in requests.

Managed Agents now support setting effort levels on model configuration, webhooks for environment and memory store lifecycle events, and session seeding with initial events. The version field is optional for agent updates, and thread event streams support deltas.

The legacy Workbench in Claude Console will be retired on August 17, 2026, and saved prompts, variables, and evals from the old Workbench are not supported in the updated version. The experimental prompt tools APIs (/v1/experimental/generate_prompt, /v1/experimental/improve_prompt, /v1/experimental/templatize_prompt) are also being retired on the same date.

Mid-conversation system messages are now available on Claude Fable 5, Claude Mythos 5, and Claude Opus 4.8 across the Claude API, Amazon Bedrock, and Google Cloud. No beta header is required.

New Admin API beta for Claude Enterprise lets organizations list members, change roles, remove members, send invites, and manage groups and custom roles. Group and custom-role endpoints require the anthropic-beta: ce-user-management-2026-07-13 beta header.

Dreams (research preview) now supports Claude Fable 5 and Claude Sonnet 5.

Expanded Access Transparency documentation for cmek_preserve events with a filter example, example event payload, and two preservation reason codes. Also clarifies that a preservation event is written whether initiated by a human reviewer or an automated safety pipeline.

You can now set an expiration when creating API keys or Admin API keys in the Claude Console, choosing a preset, custom duration, or Never. Keys with a lifetime of at least 7 days trigger an email reminder before expiration.

Added the agent-memory-2026-07-22 beta header, which changes listing memories to return results in a stable server-defined order, ignores order_by and order, restricts depth to 0 or 1, and tightens path_prefix matching. Page cursors from the old header are invalid; restart from the first page. This header replaces managed-agents-2026-04-01 on memory store endpoints, and both headers together return a 400 error.

We've restored access to Claude Fable 5 and Claude Mythos 5. See our statement for more information.

We've launched Claude Sonnet 5 (claude-sonnet-5), the next generation of our Sonnet model family, at introductory pricing of $2 / $10 per MTok through August 31, 2026 (standard $3 / $15 thereafter). Claude Sonnet 5 supports a 1M token context window, 128k max output…

Claude Managed Agents session event streams now support event deltas. Opt in with the event_deltas[] query parameter on GET /v1/sessions/{session_id}/events/stream. Listing sessions now supports backward pagination with prev_page cursor. When creating a session, you can…

We've removed fast mode for Claude Opus 4.6. Requests to claude-opus-4-6 with speed: "fast" no longer run at fast speed or premium pricing: they run at standard speed, are billed at standard rates, and do not return an error. The response's usage.speed field reports the…

Rate limits for Claude Sonnet and Haiku now match Opus at every usage tier. Three consolidated tiers (Start, Build, Scale) replace the previous structure, moving most organizations to a higher tier with no downgrades.

Rate limits raised across the Claude API. Claude Sonnet and Claude Haiku rate limits now match Claude Opus at every usage tier. Usage tiers consolidated into three: Start, Build, and Scale. Most organizations move to a higher tier, no organization receives lower limits than…

Fast mode for Claude Opus 4.7 deprecated, with removal on July 24, 2026. After removal, requests to claude-opus-4-7 with speed: "fast" will return an error. Migrate to fast mode for Claude Opus 4.8.

Fast mode is deprecated for Claude Opus 4.7, with removal on July 24, 2026. After removal, requests to claude-opus-4-7 with speed: "fast" will return an error.