> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/street-names-and-numbering.md). # Street names and numbering A critical step in the creation of an address is undertaken within each Local Authority by the dedicated Street Name and Numbering (SNN) custodian and the Scottish Local Street Gazetteer (LSG) custodians, who allocates the official street name and building information. The SNN/LSG custodian has a statutory obligation to provide SNN/LSG information for all addresses within their administrative area. Once the SNN/LSG custodian has fulfilled their statutory obligation for initial capture, the LLPG/OSG custodian will maintain the address for the life of the address record. The official street name and building information for new properties captured by the SNN/LSG custodians is provided to Royal Mail who then allocate a postcode to the address. --- # 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 by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.os.uk/os-downloads/products/addresses-and-names-portfolio/addressbase-fundamentals/street-names-and-numbering.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. 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.