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Anish Gandhi Claude Opus 5.5 Connect on LinkedIn

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Opus 5.5 in Claude chat

Nothing breaks, and Anthropic says the app needs no changes from you. Here is what you will notice, and the settings that are yours to change.

In 30 seconds

  • Nothing to set up. Opus 5.5 is first in the model menu on Pro, Max, Team and Enterprise plans. Free plans do not include Opus models.
  • Effort is the dial. It always thinks before answering. Pick a lower effort for quick answers and a higher one for hard problems.
  • Another model may answer. A few sensitive topics are answered by an older model, with a notice saying so.
  • More room. Higher five-hour , and a spare to use when you choose.

What changes for you

Open How to for where to click. Pick the model you used before to hide what does not apply to you.

Before Opus 5.5, I used

  1. Changes quietly

    Some messages are answered by another model

    If a message looks like security testing, risky biology or building other AI models, an older model answers it instead. A notice says so, and the reply is labelled with the model that wrote it.

    • Coming from Opus 4.8 Opus 4.8 is the model that security questions are handed to, so you may see it answer again.
    • Coming from Opus 5 On Opus 5 only security questions were handed on, to Opus 4.8. Biology and AI-building questions are new, and they go to Opus 5.
    • Coming from Fable 5.1 Fable 5.1 hands on the same kinds of message, to the same models.
    How to
    1. After a switch, the model menu stays on the older model for the rest of that chat. Pick Opus 5.5 again when you want it back.
    2. To be asked instead: Settings > Capabilities, turn off . A flagged message then pauses, so you can reword it and try again.
    3. Asking Claude to write out its private reasoning word for word is refused, with no switch.

    Source: Why Claude switched models (Help Center)

  2. Good to know

    Effort is the one dial

    Opus 5.5 always before it answers, and there is no switch to stop it. To get quicker or more careful answers, change the level instead.

    • Coming from Opus 4.8 If you turned thinking off for quick answers before, a lower effort level is the way to do that now.
    • Coming from Opus 5 Same as Opus 5, where thinking could not be turned off either.
    • Coming from Fable 5.1 Same as Fable 5.1, where thinking could not be turned off either.
    How to
    1. Levels run from Low to Max. The level Anthropic recommends for each model is marked Default in the menu, and it can differ between models, so check it after you switch.
    2. You can change the model or the effort level at any point in a chat. The change applies from Claude's next reply.
    3. Start at Default. Go higher only when an answer falls short, because higher levels use more of your .

    Source: Choosing a model, effort and thinking (Help Center)

  3. Good news

    More room in your five-hour limit

    Anthropic raised the five-hour on Pro, Max, Team and seat-based Enterprise plans when Opus 5.5 launched, and gave subscribers a to use when they choose.

    How to
    1. To use the reset: Settings > Usage, in a browser or Claude Desktop, then Reset for free. It is not in the phone app.
    2. Weekly limits still reset on their usual day, whether you use it or not.
    3. If your reset expires, the date is shown in Settings > Usage.

    Source: Introducing Claude Opus 5.5

Sources

Every fact on this page comes from Anthropic's own documentation, checked on 23 Sep 2026, unless it is labelled as a tester's report. Numbers from testers come from one small team with early access. Treat them as early impressions.

Anthropic's documentation