# Cognitive Search Documentation: ### What is Cognitive Search? It is a search as a service that gives a developer an API to add a search experience through a user defined index ### Index definition A user defined Object that lets cognitive search know what to return based on certain fields **Fields Include:** * Searchable - Allows a field to be searched * Facetable - Allows a field to be counted * Retrievable - Cannot be searched, but the field name will be returned * Filterable - Indicates whether to enable the field to be referenced in $filter queries * Sortable - Indicates whether to enable the field to be referenced in $orderby expressions ### Important Classes **SearchClient** * Searching your indexed documents using rich queries and powerful data shaping * Autocompleting partially typed search terms based on documents in the index * Suggesting the most likely matching text in documents as a user types * Adding, Updating or Deleting Documents documents from an index **SearchIndexClient** * Create, delete, update, or configure a search index * Declare custom synonym maps to expand or rewrite queries **SearchIndexerClient** * Start indexers to automatically crawl data sources * Define AI powered Skillsets to transform and enrich your data ### Consuming Cognitive Search * Create an index for a document using **SearchIndexClient**. * Get/Search a document from an index using **SearchClient** * Add documents into an index: based on the index definition, the library will look for the documents in the data source to add it to the index. --- # 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://ecfmg.gitbook.io/azure-serverless-quickstart/cognitive-search.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.