generated: '2026-08-27'
method: searched
source: https://platform.claude.com/docs/en/release-notes/overview
scheme: date-based
current_version: '2023-06-01'
notes: The Claude Platform release notes are the source of truth; this captures the recent window only.
  Claude Code has a separate CHANGELOG.md, and Claude Apps have separate release notes.
entries:
- date: '2026-08-26'
  breaking: false
  highlights: Compliance API session endpoints out of beta for Cowork and Claude Code sessions; local
    session endpoints now also return Claude Science and Claude for Microsoft 365 transcripts (beta, Enterprise).
    Admin API now available in the ant CLI and the Python, TypeScript, C#, Go, Java, PHP and Ruby SDKs
    under client.beta.organization — usage/cost reports and Claude Enterprise user-management remain curl-only.
- date: '2026-08-20'
  breaking: true
  highlights: Python SDK v1.0. HTTP layer moves from httpx to httpx2; requires Python 3.10+; removes the
    legacy Text Completions API and the temperature, top_p and top_k parameters on Messages methods; async
    .with_raw_response now needs await response.parse(); AnthropicBedrock errors instead of defaulting
    to us-east-1. Computer use and browser use toolsets (computer_toolset_20260801, browser_toolset_20260801)
    reach Google Cloud.
- date: '2026-08-19'
  breaking: true
  highlights: Computer use out of beta as computer_toolset_20260801 (changes request shape for existing
    integrations). Browser use tool launched. Files API out of beta — files-api-2025-04-14 header no longer
    required, and requests without it get the new response format (file expiration, page/next_page pagination,
    ids[] filter). Agent Skills and the Skills API out of beta — skills-2025-10-02 header no longer required.
    Admin API Claude Enterprise user-management out of beta.
- date: '2026-08-18'
  breaking: false
  highlights: Workbench renamed to Playground in the Claude Console (platform.claude.com/playground);
    supports every Messages API parameter and shows the full SDK request and API response per run.
- date: '2026-08-11'
  breaking: false
  highlights: Compliance API returns Cowork and Claude Code transcripts from users machines (beta, Enterprise).
    New anthropic-workspace-id response header carries the wrkspc_-prefixed workspace the request resolved
    to.
- date: '2026-08-10'
  breaking: false
  highlights: Claude Sonnet 5 introductory pricing ($2/$10 per MTok) becomes the standard price; the scheduled
    2026-09-01 increase to $3/$15 will not occur.
- date: '2026-08-07'
  breaking: false
  highlights: Managed Agents session budgets (hard spend cap; session pauses with stop reason budget_reached).
    Session advisor. inference_geo pinning for agents and sessions.
- date: '2026-08-05'
  breaking: true
  highlights: Claude Opus 4.1 (claude-opus-4-1-20250805) RETIRED — all requests now return an error. Inference
    hooks in beta for Enterprise orgs.
- date: '2026-08-03'
  breaking: false
  highlights: Compliance API returns Cowork session transcripts started on claude.ai web/mobile (beta,
    Enterprise).
- date: '2026-08-01'
  breaking: false
  highlights: Dreams (research preview) supports Claude Opus 5.
- date: '2026-07-24'
  breaking: true
  highlights: 'Claude Opus 5 launched (claude-opus-5): 1M context default and max, 128k max output, thinking
    on by default, $5/$25 per MTok. BREAKING on Opus 5: thinking:{"type":"disabled"} with effort xhigh
    or max returns 400. Fast mode REMOVED for Claude Opus 4.7 — speed:"fast" now errors with no fallback.
    Mid-conversation tool changes in beta. fallbacks gains a "default" mode.'
- date: '2026-07-22'
  breaking: false
  highlights: effort on Managed Agents agent model config. Webhooks extended to environment.* (4 types)
    and memory_store.* (3 types). Sessions accept initial_events (up to 50) on POST /v1/sessions. version
    now optional on agent update (supply for optimistic concurrency, 409 on mismatch). Session thread
    streams support event_deltas[].
- date: '2026-07-15'
  highlights: Mid-conversation system messages available on Claude Fable 5, Mythos 5, and Opus 4.8 across
    Claude API, Bedrock, and Vertex AI (no beta header).
  breaking: false
- date: '2026-07-14'
  highlights: Admin API user management for Claude Enterprise (claude.ai) orgs in beta — list/lookup members,
    change roles, invites, groups, custom roles.
  breaking: false
- date: '2026-07-10'
  highlights: Dreams (research preview) adds Fable 5 and Sonnet 5; Access Transparency cmek_preserve events
    expanded.
  breaking: false
- date: '2026-07-08'
  highlights: API key and Admin API key expiration dates configurable in the Console; Admin API reports
    expires_at.
  breaking: false
- date: '2026-07-02'
  highlights: New agent-memory-2026-07-22 beta header changes memory list behavior; SDKs updated (Python
    0.116.0, TS 0.110.0, Go 1.56.0, Java 2.48.0, Ruby 1.55.0, PHP 0.36.0, C# 12.35.0, CLI 1.16.0).
  breaking: true
- date: '2026-07-01'
  highlights: Restored access to Claude Fable 5 and Claude Mythos 5.
  breaking: false
- date: '2026-06-30'
  highlights: Launched Claude Sonnet 5 (claude-sonnet-5) with 1M context, 128k output, new tokenizer (~30%
    more tokens), adaptive thinking on by default; manual extended thinking removed (400 error).
  breaking: true
- date: '2026-06-29'
  highlights: Removed fast mode for Claude Opus 4.6 (requests run at standard speed/rates, no error).
  breaking: true
- date: '2026-06-26'
  highlights: Rate limits raised across the API; usage tiers consolidated into three (Start, Build, Scale).
  breaking: false
- date: '2026-06-22'
  highlights: MCP tunnels management API moved from Admin API /v1/organizations/tunnels to Claude API
    /v1/tunnels (mcp-tunnels-2026-06-22 header, workspace:manage_tunnels WIF scope).
  breaking: true
- date: '2026-06-18'
  highlights: SDKs add code_execution_20260120 (REPL state persistence; minimum for programmatic tool
    calling).
  breaking: false
- date: '2026-06-15'
  highlights: Retired Claude Sonnet 4 (claude-sonnet-4-20250514) and Claude Opus 4 (claude-opus-4-20250514);
    requests now error.
  breaking: true
- date: '2026-06-09'
  highlights: Launched Claude Fable 5 (claude-fable-5) and Claude Mythos 5 (claude-mythos-5) with 1M context,
    always-on adaptive thinking; released beta Apple Foundation Models Swift package.
  breaking: false
docs: https://platform.claude.com/docs/en/release-notes/overview
source_note: The previously recorded source https://platform.claude.com/docs/en/release-notes/api now
  returns 404 (verified 2026-08-27); /release-notes/overview is the live page. Claude Code keeps a separate
  CHANGELOG.md at https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md and Claude Apps have
  their own release notes in the Help Center.
window: 2026-07-01 through 2026-08-26 (recent window only)
entry_count: 25