System Prompt Editor & Analyzer

Stats

Characters

0

Words

0

Lines

1

Estimated Tokens (claude)

0

Context Limits

4K4,096
8K8,192
16K16,384
32K32,768
65K65,536
128K128,000
200K200,000

Pro tips: Use XML tags like <system>, <context>, and <instructions> to structure your prompt. Define variables with {{variable}} syntax.

What This Tool Does

System Prompt Editor & Analyzer is built for deterministic developer and agent workflows.

Write and analyze AI system prompts with live token counting, variable detection, and XML highlighting. Free online prompt editor for Claude, GPT, and more.

Use How to Use for execution steps and FAQ for constraints, policies, and edge cases.

Last updated:

This tool is provided as-is for convenience. Output should be verified before use in any production or critical context.

Agent Invocation

Best Path For Builders

Browser workflow

Runs instantly in the browser with private local processing and copy/export-ready output.

Browser Workflow

This tool is optimized for instant in-browser execution with local data handling. Run it here and copy/export the output directly.

/system-prompt-editor/

For automation planning, fetch the canonical contract at /api/tool/system-prompt-editor.json.

How to Use System Prompt Editor & Analyzer

  1. 1

    Write or paste your prompt

    Enter a system prompt from scratch or paste an existing one. The editor provides syntax highlighting and keeps your text organized.

  2. 2

    Monitor token count

    The tool shows real-time token count as you type. Keep system prompts under 500-1000 tokens to preserve context for actual conversation. Switch between token counter models if needed.

  3. 3

    Analyze prompt structure

    Well-structured prompts follow: Role/Goal → Instructions → Examples → Output Format. Use the editor to reorganize and clarify. Test edge cases in your instructions.

  4. 4

    Test prompt quality

    Paste your prompt into an AI interface and test it with real queries. Note any ambiguities, unclear instructions, or unexpected behaviors. Refine based on actual results.

Frequently Asked Questions

What is System Prompt Editor?
System Prompt Editor is a specialized text editor for writing AI system prompts. It features live token counting, variable detection, and XML tag highlighting to help you craft effective prompts.
How do I use System Prompt Editor?
Write or paste your system prompt in the editor. The tool automatically counts tokens, detects template variables like {{name}}, highlights XML tags, and shows a live analysis of your prompt structure.
Is System Prompt Editor free?
Yes. This tool is free to use with immediate access—no account required.
Does System Prompt Editor store or send my data?
No. All processing happens entirely in your browser. Your prompts stay on your device — nothing is sent to any server.
Which AI models does System Prompt Editor count tokens for?
It estimates token counts for major models including Claude, GPT, and Gemini. This helps you stay within context window limits when designing system prompts.