--- before/brief.mjs
+++ after/brief.mjs
@@
-export function buildBrief(input) {
-  return [
-    `Goal: ${input.goal.trim()}`,
-    `Stack: ${input.stack.trim()}`,
-    `Current state: ${input.current.trim()}`
-  ].join("\n");
-}
+const limits = { goal: 500, stack: 160, current: 800 };
+
+function normalize(value, limit) {
+  return String(value ?? "").replace(/\s+/g, " ").trim().slice(0, limit);
+}
+
+export function buildBrief(input = {}) {
+  const goal = normalize(input.goal, limits.goal);
+  if (!goal) throw new TypeError("A primary goal is required");
+
+  const stack = normalize(input.stack, limits.stack) || "To confirm";
+  const current = normalize(input.current, limits.current) || "To confirm";
+  return [`Goal: ${goal}`, `Stack: ${stack}`, `Current state: ${current}`].join("\n");
+}