Stop Claude's Em Dashes with One Line in Preferences or Claude.md

A Reddit user discovered a simple prompt addition to suppress Claude's overuse of em dashes. In a post titled "Don't like em dashes? Add this to your preferences or .md", user u/shiftingsmith shared a verbatim line that, when added as a standalone sentence to your Claude.ai profile preferences or Claude.md, reportedly eliminates ~98% of em dashes in outputs.
The Magic Line
Copy and paste the following as a new line in your profile preferences (Claude.ai) or Claude.md. Do not bury it in other text — add a new line before and after.
CLAUDE NEVER USES EM DASHES. Instead, ALWAYS use commas or hyphens.How It Works
The key is giving Claude an explicit alternative. Simply saying "don't use em dashes" is less effective because Claude needs to know what to do instead. By saying "ALWAYS use commas or hyphens", you provide a clear replacement behaviour.
Note: The user cautions that em dashes may still appear in edge cases — specifically "if you go out of distribution or very close to overfitting old literature and academic stuff" — but expects a 98% reduction in normal usage.
Who It's For
Anyone using Claude.ai or the API with Claude.md customization who finds em dashes distracting or against their style guide.
📖 Read the full source: r/ClaudeAI
👀 See Also

Run Claude Code in VSCode/Cursor Integrated Terminal for Better Workflow
Running Claude Code in the VSCode or Cursor integrated terminal instead of an external terminal provides immediate access to git diff panels and debuggers without switching windows, with no configuration required.

How to Stop Hitting Claude Limits: Treat Each Session Like a Token Budget
User shares how they fixed daily Claude limits by stopping message bloat — scope the task, load only relevant context, clear after each session. Includes practical workflow & infographic.

Claude's /btw Command Enables Parallel Communication During Tasks
Claude AI now supports a /btw command that lets users communicate with the AI while it's actively working on a task, allowing questions, additional instructions, or clarifications without interrupting the current workflow.

Multi-model routing reduces OpenClaw API costs by 50%
A developer cut OpenClaw API costs by 50% by routing different tasks through different models: Claude for complex reasoning, DeepSeek for file operations and test generation, and Gemini or GPT for mid-range tasks.