Check Upstream Before Building It Yourself

The most expensive code is the code that did not need to be written. A workaround built around a dependency's behaviour has to be designed, reviewed, tested, documented, and then carried forever — and if the dependency already fixed it, all of that is waste that also has to be un-built later.

When This Skill Activates

Any time the plan is to work around something rather than with it:

• A shim, polyfill, wrapper, patch, guard, or "our own version of X"
• A patch-package entry, a vendored copy of third-party code, a monkey-patch
• Re-implementing behaviour a framework already owns (routing, hydration, form state, serialisation, auth, validation)
• Any sentence of the form "the framework doesn't do X, so we…"