# Delimiters

> Delimiters are explicit markers, such as XML-style tags, triple quotes, or headings, that separate the parts of a prompt so the model can tell instructions, data, and examples apart.

- Identifier: PTL-0014
- Category: Foundations
- Canonical URL: https://protologue.com/t/delimiters/
- Also known as: XML tags, separators

## Description

Vendor guidance recommends delimiters to reduce ambiguity, make outputs easier to parse, and lower the chance that content inside a document is mistaken for an instruction. Tags can also be requested in the output for reliable extraction.

## Related terms

- [Prompt Template](https://protologue.com/t/prompt-template/)
- [Structured Outputs](https://protologue.com/t/structured-outputs/)
- [Spotlighting](https://protologue.com/t/spotlighting/)

## Sources

- Anthropic (2026). Prompting best practices. https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices
- OpenAI (2024). Prompt engineering. https://developers.openai.com/api/docs/guides/prompt-engineering

## Cite this entry

Protologue. (2026). Delimiters. In Protologue: A Taxonomy of Prompting and LLM Techniques (v1.0.0, PTL-0014). https://protologue.com/t/delimiters/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)