[MODEL] Claude uses informal/colloquial language in narration by default

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude ignored my instructions or configuration

What You Asked Claude to Do

Run routine engineering tasks — file editing, configuration updates, infrastructure automation.

What Claude Actually Did

Claude narrated its actions using casual, colloquial language by default. Examples observed: "finagling the config," "wrangling dependencies," "spinning up the server." No informal language was requested, and no configuration was set to enable it.

Expected Behavior

Claude should use precise, professional technical language matching the register of production engineering tooling. Example: "Updating the configuration file" not "finagling the config."

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

1. Start any Claude Code session with no CLAUDE.md present
2. Ask Claude to perform any multi-step task (edit a file, update a config, refactor code)
3. Observe the narration language used to describe actions

Claude Model

Sonnet

Relevant Conversation

Claude said: "I'll start by finagling the config to point at the right endpoint..."

Impact

Low - Minor inconvenience

Claude Code Version

2.1.75 (Claude Code)

Platform

Anthropic API

Additional Context

The informal register actively undermines professional credibility during stakeholder screen shares and demos. The current workaround is adding a Communication Style directive to ~/.claude/CLAUDE.md, but professional-register language should be the default — not something users need to explicitly configure. A global communicationStyle setting in settings.json (similar to spinnerTipsOverride) would be the proper fix.