# X_BUDGET_PARAMS_UNDECLARED

## Means

a dynamic route with a budget declares no prerender() paths to weigh it by

## Typical cause

The budgets step: the build renders an app/ route only to weigh it, and a route with params needs one real path to render

## Fix

add prerender: () => [{ <param>: '<a real value>' }] to the route's defineRoute, then x build --target static

[CLI and verify](/error-codes#cli-and-verify)