[BUG] outputStyle only accepts PascalCase values; lowercase values are ignored

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

<img width="665" height="111" alt="Image" src="https://github.com/user-attachments/assets/a299d0cf-72a2-4830-b616-72e56accd1a4" />

JSON schema (https://www.schemastore.org/claude-code-settings.json) documents lowercase examples

Setting outputStyle to the lowercase names shown in the docs/schema (e.g. "explanatory" or "learning") leaves Claude Code in the default style. The same config begins working immediately if I change the value to PascalCase ("Explanatory" / "Learning").

In short, the implementation is case-sensitive while the documentation and JSON schema examples are lowercase, so users following the docs never get the style they requested.

What Should Happen?

Lowercase style names ("explanatory" / "learning") should activate the corresponding built-in styles, matching the documentation and schema examples.

Error Messages/Logs

Steps to Reproduce

1. Confirm you are on Claude Code 2.0.1 (claude --version).
2. In your project, create .claude/settings.json with:

``json
{
"outputStyle": "explanatory"
}
``

1. Start claude and run /output-style or any coding task.

• Expected: Explanatory style behavior.
• Actual: CLI still reports default, and responses lack Explanatory-style guidance.

1. Edit the same file to use "Explanatory" (PascalCase), restart claude, and observe the style now activates immediately.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.1 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_