---
title: Extensibility
slug: eprescribing/guide/extensibility
docTags: 
createdAt: 2026-06-16T18:12:15.476Z
---

# Extensibility Requirements

Extensibility was added to allow trading partners a consistent way to include additional information in the SCRIPT messages. It was created to enable the integration of extra information in messages in a safe and meaningful way. It can help streamline testing of new data elements, maintain the standard's simplicity while accommodating uncommon use cases, and most importantly, paves a quicker path to introducing new features that benefit patients, providers, pharmacies, and payers.

- Surescripts will not validate data in extensions beyond the schema requirements.
- It is recommended that partners do not reject transactions that include an extension that is not expected and instead ignore the information.

:::hint{type="warning"}
**Reference: **XML Standard Guide, V2022071, Sec. 4: Pages 11 - 22
:::

When using extensions the following rules as defined by NCPDP that must be observed:

- The core schema must be followed.
- Extensions must not contradict the base standard.
- Extensions must not alter content from the base standard.
- Extensions must not be used when standard fields are available.
- External Code List values cannot be modified by extensions.
- Extensions must not be sent unless published in an approved registry maintained by NCPDP, unless there is a trading partner agreement with the ultimate receiver.