> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/higher-learning/bsv-academy/bitcoin-script-new/introduction-to-op_push_tx.md). # Introduction to OP\_PUSH\_TX What if a Bitcoin script could examine its own transaction — inspect where funds came from, how much is being moved, and exactly where they are going — all without trusting any external party? That is precisely what **OP\_PUSH\_TX** makes possible. By requiring the spending party to submit the full **transaction pre-image** as part of the unlocking data, a script gains the ability to validate transaction fields from inside the script itself. This transforms Bitcoin Script from a simple authorization layer into a **stateful computation engine** capable of enforcing complex, multi-step processes. This course introduces the mechanics of OP\_PUSH\_TX — beginning with the theoretical foundation of **Turing machines** and how they map onto Bitcoin's ledger model, then moving through the **Elliptic Curve signature process** that underpins the technique, and finally walking through each of the **11 transaction pre-image fields** and the powerful checks each enables. By the end, you will understand not only how OP\_PUSH\_TX works but how to use its individual components to build stateful, constraint-enforcing Bitcoin applications. --- # 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://hub.bsvblockchain.org/higher-learning/bsv-academy/bitcoin-script-new/introduction-to-op_push_tx.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.