diff --git a/src/engine/edge.test.ts b/src/engine/edge.test.ts
index d0e7852..8f5517b 100644
--- a/src/engine/edge.test.ts
+++ b/src/engine/edge.test.ts
@@ -207,3 +207,16 @@ describe("regressions", () => {
     expect(v?.kind).toBe("date");
   });
 });
+
+describe("review fixes", () => {
+  it("random() with no arguments returns a value in [0,1]", () => {
+    const r = calc("random()");
+    expect(r).not.toBeNull();
+    const v = Number(r);
+    expect(v).toBeGreaterThanOrEqual(0);
+    expect(v).toBeLessThanOrEqual(1);
+  });
+  it("random() participates in arithmetic", () => {
+    expect(calc("random() + 1")).not.toBeNull();
+  });
+});
diff --git a/src/engine/evaluator.ts b/src/engine/evaluator.ts
index 2431251..2dc95ca 100644
--- a/src/engine/evaluator.ts
+++ b/src/engine/evaluator.ts
@@ -529,6 +529,7 @@ function evalAgg(name: "sum" | "avg" | "prev" | "count" | "min" | "max" | "produ
 function evalCall(name: string, args: Value[], ctx: EvalCtx): Value {
   const custom = ctx.reg.customFuncs.get(name);
   if (custom) return custom(args);
+  if (name === "random") return evalRandom(args, ctx); // random() is valid with no args
 
   const x = args[0];
   if (!x) throw new EvalError(`${name} needs an argument`);
@@ -570,16 +571,6 @@ function evalCall(name: string, args: Value[], ctx: EvalCtx): Value {
     case "ceil": return x.kind === "quantity" ? { ...x, value: x.value.ceil() } : qty(n().ceil());
     case "floor": return x.kind === "quantity" ? { ...x, value: x.value.floor() } : qty(n().floor());
     case "fact": case "factorial": return qty(factorial(n()));
-    case "random": {
-      const seed = strHash(ctx.line.lineText) ^ (ctx.line.index * 0x9e3779b9);
-      const rand = mulberry32(seed);
-      if (args.length === 0) return qty(new Decimal(rand));
-      const toNum = (v: Value) => v.kind === "quantity" ? v.value.toNumber() : 0;
-      const [lo, hi] = args.length === 1 ? [0, toNum(args[0]!)] : [toNum(args[0]!), toNum(args[1]!)];
-      const isInt = Number.isInteger(lo) && Number.isInteger(hi);
-      const raw = isInt ? Math.floor(rand * (hi - lo + 1)) + lo : rand * (hi - lo) + lo;
-      return qty(new Decimal(raw));
-    }
     case "until": {
       if (x.kind !== "date") throw new EvalError("until needs a date");
       return evalDateArith("minus", x, { kind: "date", ms: startOfToday(), hasTime: false });
@@ -592,6 +583,17 @@ function evalCall(name: string, args: Value[], ctx: EvalCtx): Value {
   }
 }
 
+function evalRandom(args: Value[], ctx: EvalCtx): Value {
+  const seed = strHash(ctx.line.lineText) ^ (ctx.line.index * 0x9e3779b9);
+  const rand = mulberry32(seed);
+  if (args.length === 0) return qty(new Decimal(rand));
+  const toNum = (v: Value) => v.kind === "quantity" ? v.value.toNumber() : 0;
+  const [lo, hi] = args.length === 1 ? [0, toNum(args[0]!)] : [toNum(args[0]!), toNum(args[1]!)];
+  const isInt = Number.isInteger(lo) && Number.isInteger(hi);
+  const raw = isInt ? Math.floor(rand * (hi - lo + 1)) + lo : rand * (hi - lo) + lo;
+  return qty(new Decimal(raw));
+}
+
 function strHash(s: string): number {
   let h = 0x811c9dc5;
   for (let i = 0; i < s.length; i++) {