fix(lockfile): stamp the current capa version when pins change

src/shared/__tests__/lockfile.test.ts

@@ -282,6 +282,21 @@ describe('lockfile', () => {
       expect(b.build().generatedAt).not.toBe('2026-01-01T00:00:00.000Z');
     });
 
+    it('stamps the current generator only when a pin changes (#310)', () => {
+      const initial: Lockfile = {
+        ...emptyLockfile(),
+        generator: 'capa@2.2.0',
+        skills: [sampleSkill],
+      };
+      const unchanged = new LockfileBuilder(initial);
+      unchanged.upsertSkill(sampleSkill);
+      expect(unchanged.build().generator).toBe('capa@2.2.0');
+
+      const added = new LockfileBuilder(initial);
+      added.upsertSkill({ ...sampleSkill, id: 'new-skill' });
+      expect(added.build().generator).toBe(emptyLockfile().generator);
+    });
+
     it('starts empty when given null', () => {
       const b = new LockfileBuilder(null);
       const lf = b.build();

src/shared/lockfile.ts

@@ -531,11 +531,13 @@ export class LockfileBuilder {
 				? { providerConfig: sortProviderConfig(this.providerConfig) }
 				: {}),
 		};
-		// Only bump generatedAt when pins/generator actually changed.
+		// Only restamp generator/generatedAt when the pins changed, so a no-op
+		// install after a capa upgrade leaves the lockfile untouched.
 		if (
 			this.initialSemanticKey === null ||
 			lockfileSemanticKey(lockfile) !== this.initialSemanticKey
 		) {
+			lockfile.generator = `capa@${VERSION}`;
 			lockfile.generatedAt = new Date().toISOString();
 		}
 		return lockfile;