diff --git a/package-lock.json b/package-lock.json
index 89ef280..44e4450 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,7 +16,8 @@
         "js-yaml": "^4.1.1"
       },
       "bin": {
-        "preflight-dev": "bin/cli.js"
+        "preflight-dev": "bin/cli.js",
+        "preflight-dev-serve": "bin/serve.js"
       },
       "devDependencies": {
         "@eslint/js": "^10.0.1",
@@ -29,7 +30,7 @@
         "vitest": "^4.0.18"
       },
       "engines": {
-        "node": ">=18"
+        "node": ">=20"
       }
     },
     "node_modules/@esbuild/aix-ppc64": {
diff --git a/src/tools/prompt-score.ts b/src/tools/prompt-score.ts
index 1cecf01..9734f9e 100644
--- a/src/tools/prompt-score.ts
+++ b/src/tools/prompt-score.ts
@@ -40,7 +40,7 @@ interface ScoreResult {
   feedback: string[];
 }
 
-function scorePrompt(text: string): ScoreResult {
+export function scorePrompt(text: string): ScoreResult {
   const feedback: string[] = [];
   let specificity: number;
   let scope: number;
@@ -59,14 +59,16 @@ function scorePrompt(text: string): ScoreResult {
   }
 
   // Scope: bounded task
-  if (/\b(only|just|single|one|specific|this)\b/i.test(text) || text.length > 100) {
+  const hasBoundingWords = /\b(only|just|single|one|specific|this)\b/i.test(text);
+  const hasBroadWords = /\b(all|every|entire|whole)\b/i.test(text);
+  if (hasBoundingWords && !hasBroadWords) {
     scope = 25;
-  } else if (/\b(all|every|entire|whole)\b/i.test(text)) {
+  } else if (hasBroadWords) {
     scope = 10;
     feedback.push("🎯 'All/every' is broad — can you narrow the scope?");
   } else {
-    scope = 10;
-    feedback.push("🎯 Scope unclear — how much should change?");
+    scope = 15;
+    feedback.push("🎯 Scope unclear — try scoping with 'only', 'just', or 'this'");
   }
 
   // Actionability: clear verb
diff --git a/tests/tools/prompt-score.test.ts b/tests/tools/prompt-score.test.ts
new file mode 100644
index 0000000..14e0b5e
--- /dev/null
+++ b/tests/tools/prompt-score.test.ts
@@ -0,0 +1,78 @@
+import { describe, it, expect } from "vitest";
+import { scorePrompt } from "../../src/tools/prompt-score.js";
+
+describe("scorePrompt", () => {
+  it("gives high specificity for file paths", () => {
+    const result = scorePrompt("Fix the bug in src/tools/prompt-score.ts");
+    expect(result.specificity).toBe(25);
+  });
+
+  it("gives high specificity for backtick identifiers", () => {
+    const result = scorePrompt("Rename `handleClick` to `onPress`");
+    expect(result.specificity).toBe(25);
+  });
+
+  it("gives low specificity for vague prompts", () => {
+    const result = scorePrompt("make it better");
+    expect(result.specificity).toBe(5);
+  });
+
+  it("gives high scope for bounding words", () => {
+    const result = scorePrompt("Fix only the login validation in auth.ts");
+    expect(result.scope).toBe(25);
+  });
+
+  it("penalizes broad scope words", () => {
+    const result = scorePrompt("Refactor all the components");
+    expect(result.scope).toBe(10);
+  });
+
+  it("does NOT give full scope just because prompt is long", () => {
+    // Regression: previously text.length > 100 gave full scope points
+    const longVague = "I want you to look at the codebase and think about what could be improved and then maybe do some things that would make it generally better overall";
+    expect(longVague.length).toBeGreaterThan(100);
+    const result = scorePrompt(longVague);
+    expect(result.scope).toBeLessThan(25);
+  });
+
+  it("bounding words override broad words", () => {
+    // "just" + "all" — broad words take precedence to be conservative
+    const result = scorePrompt("Fix just all the tests");
+    expect(result.scope).toBe(10);
+  });
+
+  it("gives high actionability for specific verbs", () => {
+    const result = scorePrompt("Rename the function to handleSubmit");
+    expect(result.actionability).toBe(25);
+  });
+
+  it("gives low actionability for vague verbs", () => {
+    const result = scorePrompt("Make the app work better");
+    expect(result.actionability).toBe(15);
+  });
+
+  it("gives high done-condition for outcome words", () => {
+    const result = scorePrompt("Fix the parser so it should return null on empty input");
+    expect(result.doneCondition).toBe(25);
+  });
+
+  it("gives A+ for excellent prompts", () => {
+    const result = scorePrompt(
+      "Fix only the `validateEmail` function in src/utils/validation.ts — it should return false for inputs without an @ symbol"
+    );
+    expect(result.grade).toMatch(/^A/);
+    expect(result.total).toBeGreaterThanOrEqual(85);
+  });
+
+  it("gives low grade for vague prompts", () => {
+    const result = scorePrompt("make it better");
+    expect(result.total).toBeLessThan(50);
+  });
+
+  it("total equals sum of components", () => {
+    const result = scorePrompt("Add a test for the login page");
+    expect(result.total).toBe(
+      result.specificity + result.scope + result.actionability + result.doneCondition
+    );
+  });
+});