{
  "id": "delimiters",
  "code": "PTL-0014",
  "term": "Delimiters",
  "aliases": [
    "XML tags",
    "separators"
  ],
  "category": "foundations",
  "definition": "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.",
  "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.",
  "example": null,
  "broader": [],
  "narrower": [],
  "related": [
    "prompt-template",
    "structured-outputs",
    "spotlighting"
  ],
  "introduced": null,
  "sources": [
    {
      "title": "Prompting best practices",
      "authors": "Anthropic",
      "year": 2026,
      "url": "https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices"
    },
    {
      "title": "Prompt engineering",
      "authors": "OpenAI",
      "year": 2024,
      "url": "https://developers.openai.com/api/docs/guides/prompt-engineering"
    }
  ],
  "url": "https://protologue.com/t/delimiters/",
  "citation": "Protologue. (2026). Delimiters. In Protologue: A Taxonomy of Prompting and LLM Techniques (v1.0.0, PTL-0014). https://protologue.com/t/delimiters/"
}