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No. 3 · 12 October 2026

This week in Claude

  1. 3.1
    API · 2026-10-07

    Claude Haiku 5.5 is out, and code written for Haiku 4.5 can break on it

    Haiku 5.5 has a 1M token context window, 128k max output and adaptive thinking with the effort parameter, but manual extended thinking (budget_tokens) and the sampling parameters temperature and top_p can break code written for Haiku 4.5.

    Try it: Before switching a Haiku 4.5 call over, read the release note's list of changed parameters and remove any budget_tokens setting.

    platform.claude.com ↗
  2. 3.2
    API · 2026-10-07

    Prompt cache reads on Sonnet 5.5 now cost half as much

    Cache reads on Sonnet 5.5 dropped from $0.20 to $0.10 per million tokens, and cache writes and every other price are unchanged.

    Try it: Nothing to do; apps that reuse a long prompt on Sonnet 5.5 just get cheaper.

    platform.claude.com ↗
  3. 3.3
    API · 2026-10-09

    Managed Agents can write their own workflows (beta)

    For work with many pieces, such as reviewing hundreds of documents, an agent can write a program that runs many agents in phases and combines their results.

    Try it: If you use Managed Agents, set the agent's multiagent field to {"type": "multiagent_20261001", "workflows": {"type": "enabled"}} with the managed-agents-2026-04-01 beta header.

    platform.claude.com ↗
  4. 3.4
    Claude Code · 2026-10-08

    Claude Code 2.1.292 to 2.1.296: hooks can fail closed, sub-agents take an effort level

    onFailure: "block" on a command or HTTP hook now blocks the action if the hook can't start, times out or exits unexpectedly, and the Agent tool takes an effort parameter for sub-agents.

    Try it: If a hook guards something you care about, add onFailure: "block" so a broken hook stops the action instead of letting it through.

    raw.githubusercontent.com ↗
  5. 3.5
    Claude app · 2026-10-07

    Max and Team plans now include monthly API credits

    The credits are for running your own apps and agents on the Claude Platform, and they roll out over a few days.

    Try it: Link a Claude Console organization in Settings > Billing (Max) or Organization settings > Billing (Team) to claim them.

    support.claude.com ↗
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