# Schemas From an Environmental perspective, schemas contain environmentally-oriented vocabularies of terms for representing machine- and human-comprehensible structured data. In other words, they are linguistic “templates”, “frames”, or “patterns” together with rules for using them to specify a potentially infinite multitude of numbers, phrases, sentences, or arguments, which represent environmental data. In the Guardian, various environmental data produced in the course of executing policy workflows are packaged into JSON documents such as verifiable credentials and verifiable presentations. Schemas define the structure and content of these verifiable documents, enabling their automatic processing and provenance verification. It’s critical that all data required to be presented and or collected during a policy workflow has a well-defined verifiable credential schema. The schema will be used in the structural conformance verification of a document within a policy workflow. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.guardianservice.app/technical-information/users/standard-registry-users-schemas-and-policies/schemas.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.