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Documentation Index

Fetch the complete documentation index at: https://code.claude.com/docs/llms.txt

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Output styles change how Claude responds, not what Claude knows. They modify the system prompt to set role, tone, and output format. Use one when you keep re-prompting for the same voice or format every turn, or when you want Claude to act as something other than a software engineer. A custom output style adds your instructions to the system prompt and lets you choose whether to keep Claude Code’s built-in software engineering instructions. Keep them when you’re changing how Claude communicates but still coding, like always answering with a diagram. Leave them out when Claude isn’t doing software engineering at all, like a writing assistant or data analyst. For instructions about your project, conventions, or codebase, use CLAUDE.md instead.

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Built-in output styles

Claude Code’s Default output style is the existing system prompt, designed to help you complete software engineering tasks efficiently. There are three additional built-in output styles:
  • Proactive: Claude executes immediately, makes reasonable assumptions instead of pausing for routine decisions, and prefers action over planning. This applies the same guidance as auto mode without changing your permission mode, so you still see permission prompts before tools run.
  • Explanatory: Provides educational “Insights” in between helping you complete software engineering tasks. Helps you understand implementation choices and codebase patterns.
  • Learning: Collaborative, learn-by-doing mode where Claude will not only share “Insights” while coding, but also ask you to contribute small, strategic pieces of code yourself. Claude Code will add TODO(human) markers in your code for you to implement.

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Change your output style

Run /config and select Output style to pick a style from a menu. Your selection is saved to .claude/settings.local.json at the local project level. To set a style without the menu, edit the outputStyle field directly in a settings file: 
{
  "outputStyle": "Explanatory"
}
Because the output style is set in the system prompt at session start, changes take effect the next time you start a new session. This keeps the system prompt stable throughout a conversation so prompt caching can reduce latency and cost.

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Create a custom output style

A custom output style is a Markdown file: frontmatter for metadata, then the instructions to add to the system prompt.
1

Create a Markdown file

Save it at one of three levels. The file name becomes the style name unless you set name in the frontmatter.
  • User: ~/.claude/output-styles
  • Project: .claude/output-styles
  • Managed policy: .claude/output-styles inside the managed settings directory
2

Add frontmatter and instructions

Decide whether to keep Claude Code’s software engineering instructions. Set keep-coding-instructions: true if you’re changing how Claude communicates but still want it coding the same way. Leave it out if Claude won’t be doing software engineering.This example leads every explanation with a diagram while keeping Claude’s coding behavior:
---
name: Diagrams first
description: Lead every explanation with a diagram
keep-coding-instructions: true
---

When explaining code, architecture, or data flow, start with a Mermaid diagram showing the structure, then explain in prose.

## Diagram conventions

Use `flowchart TD` for control flow and `sequenceDiagram` for request paths. Keep diagrams under 15 nodes.
3

Switch to your style

Run /config and select your style under Output style. It takes effect the next time you start a session.
Plugins can also ship output styles in an output-styles/ directory.

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Frontmatter

Output style files support these frontmatter fields:
FrontmatterPurposeDefault
nameName of the output style, if not the file nameInherits from file name
descriptionDescription of the output style, shown in the /config pickerNone
keep-coding-instructionsKeep Claude Code’s built-in software engineering instructionsfalse
force-for-pluginPlugin output styles only: apply this style automatically whenever the plugin is enabled, without requiring users to select it. Overrides the user’s outputStyle setting. If multiple enabled plugins set this, Claude Code uses the first one loaded.false

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How output styles work

Output styles directly modify Claude Code’s system prompt.
  • All output styles have their own custom instructions added to the end of the system prompt.
  • All output styles trigger reminders for Claude to adhere to the output style instructions during the conversation.
  • Custom output styles leave out Claude Code’s built-in software engineering instructions, such as how to scope changes, write comments, and verify work, unless keep-coding-instructions is set to true.
Token usage depends on the style. Adding instructions to the system prompt increases input tokens, though prompt caching reduces this cost after the first request in a session. The built-in Explanatory and Learning styles produce longer responses than Default by design, which increases output tokens. For custom styles, output token usage depends on what your instructions tell Claude to produce. Several features customize how Claude Code behaves. Output styles modify the system prompt directly and apply to every response. The others add instructions without changing the default system prompt, or scope them to a specific task.
FeatureHow it worksUse it when
Output stylesModifies the system promptYou want a different role, tone, or default response format every turn
CLAUDE.mdAdds a user message after the system promptClaude should always know your project conventions and codebase context
--append-system-promptAppends to the system prompt without removing anythingYou want a one-off addition for a single invocation
AgentsRuns a subagent with its own system prompt, model, and toolsYou want a separately scoped helper for a focused task
SkillsLoads task-specific instructions when invoked or relevantYou have a reusable workflow
  • Settings: where the outputStyle field lives and how settings precedence works
  • Permission modes: the Proactive style mirrors auto mode without changing your permission mode
  • Plugins: package and distribute output styles alongside skills, hooks, and agents
  • Debug your configuration: diagnose why an output style isn’t taking effect