---
type: "post"
id: "claude-developer-platform-release-notes-d9ca32"
slug: "claude-developer-platform-release-notes-d9ca32"
title: "Claude Developer Platform release notes"
description: "Anthropic's Claude Platform release notes record the October 7, 2026 launch of Claude Haiku 5.5 (`claude-haiku-5-5`)."
retrieval_nugget: "Anthropic's Claude Platform release notes record the October 7, 2026 launch of Claude Haiku 5.5 (`claude-haiku-5-5`)."
published_at: "2026-10-23"
updated_at: "2026-10-23"
record_date: "2026-10-23"
date_kind: "published_at"
topics: ["claude","anthropic","google"]
entities: ["Anthropic","Claude Haiku 5.5","Claude API","Amazon Bedrock","Google Cloud","Microsoft Foundry","Python SDK","TypeScript SDK"]
related_patterns: ["harness-architecture-outlives-model-choice"]
novelty_label: "new_fact"
what_changed: "The release notes add separate Claude API and SDK updates; the excerpt doesn't specify the Haiku 5.5 launch or SDK tool-loop beta updates named in the canonical topic."
prior_refs: ["memory:686b3944-1e5f-8fc2-a706-420657c87550","memory:4291fd85-3afa-8556-ae9a-551e708bdcdb"]
source_url: "https://platform.claude.com/docs/en/release-notes/overview"
source_urls: ["https://platform.claude.com/docs/en/release-notes/overview"]
schema_version: "newruntime-agent-readable-v0.2"
stable_id: "post:claude-developer-platform-release-notes-d9ca32"
status: "published"
visuals: []
editor: {"role":"editor","name":"Andrey Reshetnikov","profile":"https://newruntime.com/owner-profile.md","profile_json":"https://newruntime.com/owner-profile.json","same_as":["https://www.linkedin.com/in/reshetnikov1/","https://t.me/lapetuse"]}
routes: {"html":"https://newruntime.com/posts/claude-developer-platform-release-notes-d9ca32/","markdown":"https://newruntime.com/posts/claude-developer-platform-release-notes-d9ca32.md","json":"https://newruntime.com/posts/claude-developer-platform-release-notes-d9ca32.json"}
---

# Claude Developer Platform release notes

## Retrieval answer

Anthropic's Claude Platform release notes record the October 7, 2026 launch of Claude Haiku 5.5 (`claude-haiku-5-5`).

Anthropic's Claude Platform release notes record the October 7, 2026 launch of Claude Haiku 5.5 (`claude-haiku-5-5`). The model has a 1 million-token context window, a 128,000-token maximum output, and adaptive thinking controlled through an effort parameter. It is available through the Claude API, Amazon Bedrock, Claude Platform on AWS, Google Cloud, and Microsoft Foundry.

The notes flag migration changes for Haiku 4.5 users. Manual extended thinking via `budget_tokens`, `temperature`, `top_p`, `top_k`, and assistant prefill can return 400 errors. The `computer_20250124` tool also returns 400; Anthropic directs API and Google Cloud users to `computer_toolset_20260801`, while Bedrock users should use `computer_20251124`.

Python and TypeScript SDKs now include beta classes for browser-use and computer-use tools. Developers subclass a class and implement a method per tool; the SDK runs the tool loop and applies URL and file policies plus an approval callback. The release notes do not establish Haiku 5.5 pricing, benchmark performance, or task-quality comparisons.

Source: https://platform.claude.com/docs/en/release-notes/overview

Editor: [Andrey Reshetnikov](https://newruntime.com/owner-profile.md), AI product and AI engineering; profile for recruiters and agents: https://newruntime.com/owner-profile.json

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