System and methods for declaration-based extension management for multi-tenant environments

A system and associated methods for enabling a tenant user of a multi-tenant computing platform to introduce an extension to the platform's functions and capabilities. A computing system, such as a distributed computing service platform, may manage independent customizations and/or extensions (collectively, "extensions") of the service platform by multiple tenants in a manner that avoids undesirable behavior that may be caused by incompatible extensions. The service may accomplish this by requiring that a proposed extension provided by a tenant or extension vendor be accompanied by a formal declaration with respect to service platform component functionality and/or service platform data objects (collectively, "service platform resources") that are utilized and/or modified by the extension. The service may further require that the extension be accompanied by validation code (e.g., one or more modules) that is capable of verifying that particular code modules or data objects of the extension are functioning as expected.