> For the complete documentation index, see [llms.txt](https://docs.catalog.cat/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.catalog.cat/technical-manual/catalog.md). # CATalog CATalog is, at a high level, a registry that allows non-expiring registrations of data hashes. Each registration creates an NFT representing the registration. By social convention, TAILs are the data being registered, and the returned NFTs are used to store and update CAT details such as name or image. The CATalog registry's state is `(cat_maker_puzzle_hash . registration_price)` , where the first argument is the CAT maker for the payment CAT, while the second variable holds the amount of the CAT to be paid for a registration. The registry launches NFTs by first creating 'uniqueness prelauncher' coins, which then create launcher coins and the eve NFTs. Uniqueness prelaunchers contain the unique data's hash (i.e., the TAIL hash) in their puzzle, allowing other dApps and APIs to efficiently verify the authenticity of the NFTs. Generally, announcements and messages from the main registry are sent using a one-byte prefix followed by a hash of the actual message contents. To prevent collisions, the prefixes and message structures are defined in a single file ([here](https://github.com/xch-dev/chia-wallet-sdk/blob/main/crates/chia-sdk-driver/src/primitives/action_layer/catalog_registry_prefix.rs)). *Written by* [*yakuhito*](https://x.com/yakuh1t0) *from* [*FireAcademy.io*](https://fireacademy.io/) *on Feb 11th, 2025.* --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://docs.catalog.cat/technical-manual/catalog.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.