What probably matters to youSection of the release
What
A fifth built-in style joins Proactive, Explanatory and Learning. Described as "Claude responds tersely, leading with results and skipping preamble and narration", it tells the model to lead with the result, cut narration, answer simple questions in 1-3 sentences and never trade correctness for brevity. Nothing gates its registration, so anyone on this build can pick it from the output-style list unless output styles are turned off entirely.
Details
Registered as a built-in style with coding instructions retained, so normal engineering guidance still applies.
Its system prompt is headed "# Concise Style Active" and states explicitly that it overrides more general communication guidance, backed by six rules plus a short reminder re-injected each turn.
Reported in prompt telemetry under its own key rather than collapsing into the generic one.
Evidence
Claude responds tersely, leading with results and skipping preamble and narration, The user chose brevity over narration. You should:
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added sinceA small documentation edit on Modifying system prompts touched a line naming /output-style after this was published.* **CLI**: run `/output-style <style>`, for example `/output-style concise`, or run `/config` and select one. The `/output-style` command requires Claude Code v2.1.269 or later.agent-sdk/modifying-system-promptssee the edit
Confirmed sinceAnthropic's documentation has since written up /output-style, on How Claude Code uses prompt caching.When you switch [output styles](/docs/en/output-styles) mid-session with `/config` or the `outputStyle` setting, Claude uses the new style starting with your next message. Claude Code delivers the new style's instructions as a message in t…prompt-cachingsee the edit
How sure we are
Two sources agreeTwo things we can check say the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up /output-style, on How Claude Code uses prompt caching.
Anthropic's release notes agreeAdded a built-in "Concise" output style: Claude leads with results and skips preamble and narration, while doing the work just as…
