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llms.txt Analyzer & Previewer

Analyze the structure and content of an llms.txt file. Preview the rendered Markdown, inspect sections and links, and calculate words, characters, file size and estimated tokens.

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What Is the llms.txt Analyzer?

The llms.txt Analyzer & Previewer is a read-only diagnostic dashboard designed to help you understand exactly what your llms.txt file contains. Instead of manually counting URLs or guessing token sizes, this tool instantly parses your file, extracts all sections and links, and builds a comprehensive statistical report.

How the Analyzer Works

When you paste or upload your file, the Analyzer runs a specialized Markdown parser entirely in your browser. It identifies the H1 project title, any blockquote summaries, introductory text, and H2 file-list sections. It then extracts every Markdown link, categorizes them as internal or external, measures their descriptions, and calculates size metrics for the entire document.

What Information the Tool Measures

The tool provides an exhaustive breakdown including total words, characters, physical lines, unique URLs, and duplicate occurrences. It also visualizes the distribution of content across your sections, making it easy to see if a single section holds 90% of your links or if your descriptions are missing.

How Estimated Token Counting Works

Because different Large Language Models (like GPT-4, Claude, or Llama) use different tokenization algorithms, it is impossible to give a single perfect token count. The Analyzer uses a standard heuristic (approximately 4 characters per token) to provide a solid baseline estimate, helping you plan your context window budgets safely.

Core vs Optional Preview

The official specification defines a special ## Optional section for secondary resources (like blogs or privacy policies). The Analyzer automatically separates this section and calculates two different token estimates: a "Core File" context and a "Full File Context." This shows you exactly how much weight your optional resources add to the payload.

Analyzer vs Validator

The Analyzer is designed to measure and visualize your file. While it may point out basic structural observations (like missing summaries or duplicate URLs), it does not enforce strict format rules. To ensure your file complies with all official recommendations, you should run it through the llms.txt Validator.

Related Components

Questions you might have

Does the Analyzer change my file?
No. It only inspects and previews the input. Editing and cleanup belong in the Formatter.
Does it validate the file?
It reports whether the structure was successfully parsed and shows basic observations. Full rule-based validation belongs in the Validator.
Are token counts exact?
No. Tokenization varies between models and tokenizer versions. Every result should be labelled as an estimate.
Is the summary required?
No. The H1 is the only required component under the current proposal.
Are link descriptions required?
No. They are optional, though brief informative descriptions are recommended.
What does the Optional preview show?
It shows the difference between the complete file and a preview that excludes links under ## Optional, reflecting how compatible processors may create shorter context.
Does the Analyzer check whether URLs work?
Not by default. Static URL counting and extraction are included, but HTTP-status checking belongs in the Link Checker.
Can external links appear in llms.txt?
Yes. The proposal notes that useful external resources may help explain a site or project.