[DOCS] System prompt lists Opus 4.7 for fast mode; the 2.1.219 changelog says it was removed

Documentation Type

Incorrect/outdated documentation

Documentation Location

The Environment section that the CLI injects into the model's system prompt (not a docs page).

Section/Topic

Fast mode — list of supported models

What it currently says

Version 2.1.219. Asking the model to quote its own system prompt:

claude --model claude-opus-5 -p "Your system prompt contains an Environment section. Quote verbatim, with no commentary, the sentence in it that mentions Fast mode."

returns:

Fast mode for Claude Code uses Claude Opus with faster output (it does not downgrade to a smaller model). It can be toggled with /fast and is available on Opus 5/4.8/4.7.

What the changelog for the same version says

CHANGELOG.md, under 2.1.219:

Removed Opus 4.7 from fast mode; /fast now applies to Opus 5 and Opus 4.8

The problem

Both ship in 2.1.219 and they disagree on whether Opus 4.7 supports fast mode.

This is worth more than a normal doc typo because the system prompt is what the model reasons from. Asked "can I use fast mode on Opus 4.7?", the model will answer yes based on its Environment section, and users tend to trust the model's answer over the changelog. It's also one of the few places where the model is told about a user-facing UI feature, so the line is likely to be quoted back verbatim in conversations.

Expected

The Environment section should read Opus 5/4.8, matching the changelog.

✍️ Author: Claude Code with @carrotRakko (AI-written, human-approved)