> For the complete documentation index, see [llms.txt](https://docs.capsulelabs.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.capsulelabs.xyz/protocol-overview/developer-walkthroughs/code-examples.md). # Code Examples The Capsule Shipping contracts serve as a highly abstracted and modular solution for packaging and shipping assets within the blockchain ecosystem. Its design enables developers to create customized user interfaces, additional business logic, and complementary smart contracts that interact with the PostOffice. With the `PostOffice.sol` contract as the core infrastructure, anyone can extend its functionality to suit their specific use cases. One can build wrapper contracts that add conditions for package redemption or shipment, leverage external data sources such as oracles to enforce rules and requirements, or anything more. Presented are example wrapper contracts that can be tailored to implement various constraints, pricing models, or eligibility criteria for package handling. --- # 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.capsulelabs.xyz/protocol-overview/developer-walkthroughs/code-examples.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.