Claude Code 2.1.237 adds Concise output style and gateway cache fix

Claude Code 2.1.237 landed August 20, 2026 with a built-in Concise output style and a prompt-cache fix for sessions that run through an LLM gateway or a custom base URL. The GitHub release and the public changelog list those two bullets and nothing else.

Concise is the change you will see in the transcript. In the changelog, Claude leads with results, skips preamble and narration, and still does the work thoroughly. @ClaudeDevs adds that responses stay short, with full detail when you ask. You select it under Output style in /config, or set "outputStyle": "Concise" in settings.json. Concise is not described as a different model, a cheaper route, or a shallower pass over the repo. If you want the essay, you ask. If you want the patch, you should see the patch.

Enable Concise in /config or settings.json

There are two documented ways to turn it on. The changelog documents Output style in /config; @ClaudeDevs adds the settings.json key.

Inside a session, open /config and set Output style to Concise. That is the path in the 2.1.237 notes and in the announcement.

To make it stick in config, set the outputStyle key in settings.json:

"outputStyle": "Concise"

That key and value are from @ClaudeDevs. This release does not document a dedicated slash command for Concise, a CLI flag, or a one-off per-turn switch.

The changelog page is generated from CHANGELOG.md on GitHub. It tells you to run claude --version to check your installed version. Concise ships in 2.1.237. It is not described as on by default. Pick it if you want it.

Prompt caching for gateways and custom base URLs

The second bullet is one line on both official write-ups: fixed prompt caching for sessions using an LLM gateway or custom base URL.

If you are not using an LLM gateway or a custom base URL, this may not be your bug. If you send traffic through an LLM gateway, or you point the client at a custom base URL, it is.

The notes do not name products, headers, error strings, or a way to confirm a cache hit after you upgrade. They name a session class and say caching for it is fixed. That is enough to set the floor: teams on a gateway or a custom base URL should be on 2.1.237 before they spend another long session on an older build.

The GitHub release v2.1.237 was published 2026-08-20T00:54:41Z. @ClaudeDevs posted at 2026-08-20T01:13:57.000Z. The docs heading is 2.1.237, August 20, 2026. The changelog and GitHub tag carry the same two bullets. @ClaudeDevs covered Concise and the enable path.

This release is only these two bullets

2.1.237 is not the prior changelog heading. This version is Concise plus the gateway and custom-base-URL cache fix.

This release does not say how Concise interacts with other output styles, whether an existing outputStyle value needs a migration, or what a fixed cache looks like in logs. Those details are unknown.

Why practitioners should care

Concise is for the person who wants the answer at the top of the block. Lead with the result. Skip the throat-clearing. Keep the work thorough. You set it once in /config or you pin outputStyle in settings.json. You do not have to re-explain the tone every session.

The cache fix is for sessions on an LLM gateway or a custom base URL. That is the deployment the bullet names. If that is how you run Claude Code, this version is a correctness upgrade, not a preference.

Neither change asks you to pick a new model or rewrite your launch flags. Concise is opt-in. The cache fix is in the build.

Next step: Run claude --version. If you are on 2.1.237, open /config and set Output style to Concise, or add "outputStyle": "Concise" to settings.json. If you use an LLM gateway or a custom base URL, install 2.1.237 first, then judge Concise on a real session.