diff --git a/CHANGELOG.md b/CHANGELOG.md
index ef4cfae..1bf3457 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 ### Breaking Changes
 
 - **Rename `ConnectionTier` value `'fast'` → `'high'`** — Aligns connection tier vocabulary with CPU, memory, and GPU tiers which all use `'low' | 'mid' | 'high'`. Update any code comparing `tiers.connection === 'fast'` to use `'high'` instead
+- **`classify()` and `deriveHints()` now accept `StoredSignals` instead of `RawSignals`** — These functions never used `userAgent` or `viewport` (which are stripped before storage). The narrower type makes the API honest. Existing call sites are unaffected — `RawSignals` is structurally assignable to `StoredSignals`
+- **`profile:store` event now carries `StoredSignals` instead of `RawSignals`** — The event previously emitted the raw probe payload (including `userAgent`/`viewport`), not what was actually stored. The `signals` field now matches the persisted data. `bot:reject` still carries `RawSignals` (it fires before stripping)
 - **middleware-fastify: normalized return shape** — `createDeviceRouter()` now returns raw Fastify hooks instead of a `fastify-plugin` wrapped plugin. Migrate `await app.register(middleware)` → `app.addHook('preHandler', middleware)`. When using `injectProbe: true`, register the injection hook separately: `app.addHook('onSend', injectionMiddleware)`. Removed `fastify-plugin` dependency
 
 ### Features
diff --git a/docs/api/types.md b/docs/api/types.md
index 83de3c4..eed5b11 100644
--- a/docs/api/types.md
+++ b/docs/api/types.md
@@ -2,9 +2,9 @@
 
 ## Functions
 
-### `classify(signals: RawSignals): DeviceTiers`
+### `classify(signals: StoredSignals): DeviceTiers`
 
-Classifies raw device signals into capability tiers.
+Classifies device signals into capability tiers.
 
 ```typescript
 import { classify } from '@device-router/types';
@@ -17,7 +17,7 @@ const tiers = classify({
 // { cpu: 'high', memory: 'high', connection: 'high', gpu: 'none' }
 ```
 
-### `deriveHints(tiers: DeviceTiers, signals?: RawSignals): RenderingHints`
+### `deriveHints(tiers: DeviceTiers, signals?: StoredSignals): RenderingHints`
 
 Derives rendering hints from device tiers.
 
@@ -224,7 +224,7 @@ type DeviceRouterEvent =
       source: ProfileSource;
       durationMs: number;
     }
-  | { type: 'profile:store'; sessionToken: string; signals: RawSignals; durationMs: number }
+  | { type: 'profile:store'; sessionToken: string; signals: StoredSignals; durationMs: number }
   | { type: 'bot:reject'; sessionToken: string; signals: RawSignals }
   | { type: 'error'; error: unknown; phase: 'middleware' | 'endpoint'; sessionToken?: string };
 ```
diff --git a/packages/middleware-express/src/__tests__/endpoint.test.ts b/packages/middleware-express/src/__tests__/endpoint.test.ts
index 691c259..ec62822 100644
--- a/packages/middleware-express/src/__tests__/endpoint.test.ts
+++ b/packages/middleware-express/src/__tests__/endpoint.test.ts
@@ -256,6 +256,31 @@ describe('createProbeEndpoint', () => {
       expect(typeof event.durationMs).toBe('number');
     });
 
+    it('strips userAgent and viewport from profile:store signals', async () => {
+      const events: DeviceRouterEvent[] = [];
+      const onEvent = vi.fn((e: DeviceRouterEvent) => {
+        events.push(e);
+      });
+
+      const handler = createProbeEndpoint({ storage, onEvent });
+      const req = createMockReq({
+        hardwareConcurrency: 4,
+        userAgent: 'Mozilla/5.0 Test',
+        viewport: { width: 1920, height: 1080 },
+      });
+      const res = createMockRes();
+
+      await handler(req, res);
+
+      const event = events.find((e) => e.type === 'profile:store') as Extract<
+        DeviceRouterEvent,
+        { type: 'profile:store' }
+      >;
+      expect(event.signals).toEqual({ hardwareConcurrency: 4 });
+      expect(event.signals).not.toHaveProperty('userAgent');
+      expect(event.signals).not.toHaveProperty('viewport');
+    });
+
     it('emits bot:reject when bot detected', async () => {
       const events: DeviceRouterEvent[] = [];
       const onEvent = vi.fn((e: DeviceRouterEvent) => {
diff --git a/packages/middleware-express/src/endpoint.ts b/packages/middleware-express/src/endpoint.ts
index cc8e4e7..68044bf 100644
--- a/packages/middleware-express/src/endpoint.ts
+++ b/packages/middleware-express/src/endpoint.ts
@@ -63,7 +63,12 @@ export function createProbeEndpoint(options: EndpointOptions) {
       await storage.set(sessionToken, profile, ttl);
       const durationMs = performance.now() - start;
 
-      emitEvent(onEvent, { type: 'profile:store', sessionToken, signals, durationMs });
+      emitEvent(onEvent, {
+        type: 'profile:store',
+        sessionToken,
+        signals: storedSignals,
+        durationMs,
+      });
 
       res.cookie(cookieName, sessionToken, {
         path: cookiePath,
diff --git a/packages/middleware-fastify/src/__tests__/endpoint.test.ts b/packages/middleware-fastify/src/__tests__/endpoint.test.ts
index aef1104..cc10fc3 100644
--- a/packages/middleware-fastify/src/__tests__/endpoint.test.ts
+++ b/packages/middleware-fastify/src/__tests__/endpoint.test.ts
@@ -215,6 +215,27 @@ describe('createProbeEndpoint', () => {
       );
     });
 
+    it('strips userAgent and viewport from profile:store signals', async () => {
+      const onEvent = vi.fn();
+      const handler = createProbeEndpoint({ storage, onEvent });
+      const req = createMockReq({
+        hardwareConcurrency: 4,
+        userAgent: 'Mozilla/5.0 Test',
+        viewport: { width: 1920, height: 1080 },
+      });
+      const reply = createMockReply();
+
+      await handler(req, reply);
+
+      const event = onEvent.mock.calls[0][0] as Extract<
+        DeviceRouterEvent,
+        { type: 'profile:store' }
+      >;
+      expect(event.signals).toEqual({ hardwareConcurrency: 4 });
+      expect(event.signals).not.toHaveProperty('userAgent');
+      expect(event.signals).not.toHaveProperty('viewport');
+    });
+
     it('emits bot:reject when bot detected', async () => {
       const onEvent = vi.fn();
       const handler = createProbeEndpoint({ storage, onEvent });
diff --git a/packages/middleware-fastify/src/endpoint.ts b/packages/middleware-fastify/src/endpoint.ts
index 132806d..aa719a4 100644
--- a/packages/middleware-fastify/src/endpoint.ts
+++ b/packages/middleware-fastify/src/endpoint.ts
@@ -64,7 +64,12 @@ export function createProbeEndpoint(options: EndpointOptions) {
       await storage.set(sessionToken, profile, ttl);
       const durationMs = performance.now() - start;
 
-      emitEvent(onEvent, { type: 'profile:store', sessionToken, signals, durationMs });
+      emitEvent(onEvent, {
+        type: 'profile:store',
+        sessionToken,
+        signals: storedSignals,
+        durationMs,
+      });
 
       reply.setCookie(cookieName, sessionToken, {
         path: cookiePath,
diff --git a/packages/middleware-hono/src/__tests__/endpoint.test.ts b/packages/middleware-hono/src/__tests__/endpoint.test.ts
index 4133a20..95fa10f 100644
--- a/packages/middleware-hono/src/__tests__/endpoint.test.ts
+++ b/packages/middleware-hono/src/__tests__/endpoint.test.ts
@@ -196,6 +196,31 @@ describe('createProbeEndpoint (hono)', () => {
       expect(typeof (event as { durationMs: number }).durationMs).toBe('number');
     });
 
+    it('strips userAgent and viewport from profile:store signals', async () => {
+      const onEvent = vi.fn();
+      const app = new Hono();
+      app.post('/probe', createProbeEndpoint({ storage, onEvent }));
+
+      const res = await app.request('/probe', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          hardwareConcurrency: 4,
+          userAgent: 'Mozilla/5.0 Test',
+          viewport: { width: 1920, height: 1080 },
+        }),
+      });
+
+      expect(res.status).toBe(200);
+      const event = onEvent.mock.calls[0][0] as Extract<
+        DeviceRouterEvent,
+        { type: 'profile:store' }
+      >;
+      expect(event.signals).toEqual({ hardwareConcurrency: 4 });
+      expect(event.signals).not.toHaveProperty('userAgent');
+      expect(event.signals).not.toHaveProperty('viewport');
+    });
+
     it('emits bot:reject when bot detected', async () => {
       const onEvent = vi.fn();
       const app = new Hono();
diff --git a/packages/middleware-hono/src/endpoint.ts b/packages/middleware-hono/src/endpoint.ts
index 983ecb1..06b18ef 100644
--- a/packages/middleware-hono/src/endpoint.ts
+++ b/packages/middleware-hono/src/endpoint.ts
@@ -66,7 +66,12 @@ export function createProbeEndpoint(options: EndpointOptions): Handler {
       await storage.set(sessionToken, profile, ttl);
       const durationMs = performance.now() - start;
 
-      emitEvent(onEvent, { type: 'profile:store', sessionToken, signals, durationMs });
+      emitEvent(onEvent, {
+        type: 'profile:store',
+        sessionToken,
+        signals: storedSignals,
+        durationMs,
+      });
 
       setCookie(c, cookieName, sessionToken, {
         path: cookiePath,
diff --git a/packages/middleware-koa/src/__tests__/endpoint.test.ts b/packages/middleware-koa/src/__tests__/endpoint.test.ts
index a4f3f4f..17beb22 100644
--- a/packages/middleware-koa/src/__tests__/endpoint.test.ts
+++ b/packages/middleware-koa/src/__tests__/endpoint.test.ts
@@ -189,6 +189,30 @@ describe('createProbeEndpoint (koa)', () => {
       expect(typeof event.durationMs).toBe('number');
     });
 
+    it('strips userAgent and viewport from profile:store signals', async () => {
+      const events: DeviceRouterEvent[] = [];
+      const onEvent = vi.fn((e: DeviceRouterEvent) => {
+        events.push(e);
+      });
+
+      const handler = createProbeEndpoint({ storage, onEvent });
+      const ctx = createMockCtx({
+        hardwareConcurrency: 4,
+        userAgent: 'Mozilla/5.0 Test',
+        viewport: { width: 1920, height: 1080 },
+      });
+
+      await handler(ctx);
+
+      const event = events.find((e) => e.type === 'profile:store') as Extract<
+        DeviceRouterEvent,
+        { type: 'profile:store' }
+      >;
+      expect(event.signals).toEqual({ hardwareConcurrency: 4 });
+      expect(event.signals).not.toHaveProperty('userAgent');
+      expect(event.signals).not.toHaveProperty('viewport');
+    });
+
     it('emits bot:reject when bot detected', async () => {
       const events: DeviceRouterEvent[] = [];
       const onEvent = vi.fn((e: DeviceRouterEvent) => {
diff --git a/packages/middleware-koa/src/endpoint.ts b/packages/middleware-koa/src/endpoint.ts
index b5ada34..2191624 100644
--- a/packages/middleware-koa/src/endpoint.ts
+++ b/packages/middleware-koa/src/endpoint.ts
@@ -65,7 +65,12 @@ export function createProbeEndpoint(options: EndpointOptions) {
       await storage.set(sessionToken, profile, ttl);
       const durationMs = performance.now() - start;
 
-      emitEvent(onEvent, { type: 'profile:store', sessionToken, signals, durationMs });
+      emitEvent(onEvent, {
+        type: 'profile:store',
+        sessionToken,
+        signals: storedSignals,
+        durationMs,
+      });
 
       ctx.cookies.set(cookieName, sessionToken, {
         path: cookiePath,
diff --git a/packages/types/src/classify.ts b/packages/types/src/classify.ts
index 323d8fa..9abca98 100644
--- a/packages/types/src/classify.ts
+++ b/packages/types/src/classify.ts
@@ -1,5 +1,5 @@
 import type {
-  RawSignals,
+  StoredSignals,
   CpuTier,
   MemoryTier,
   ConnectionTier,
@@ -68,7 +68,7 @@ export function classifyGpu(
   return 'mid';
 }
 
-export function classify(signals: RawSignals, thresholds?: TierThresholds): DeviceTiers {
+export function classify(signals: StoredSignals, thresholds?: TierThresholds): DeviceTiers {
   return {
     cpu: classifyCpu(signals.hardwareConcurrency, thresholds?.cpu),
     memory: classifyMemory(signals.deviceMemory, thresholds?.memory),
diff --git a/packages/types/src/events.ts b/packages/types/src/events.ts
index 153feb5..0e16812 100644
--- a/packages/types/src/events.ts
+++ b/packages/types/src/events.ts
@@ -1,4 +1,10 @@
-import type { DeviceTiers, RenderingHints, RawSignals, ProfileSource } from './profile.js';
+import type {
+  DeviceTiers,
+  RenderingHints,
+  StoredSignals,
+  RawSignals,
+  ProfileSource,
+} from './profile.js';
 
 export type DeviceRouterEvent =
   | {
@@ -12,7 +18,7 @@ export type DeviceRouterEvent =
   | {
       type: 'profile:store';
       sessionToken: string;
-      signals: RawSignals;
+      signals: StoredSignals;
       durationMs: number;
     }
   | {
diff --git a/packages/types/src/hints.ts b/packages/types/src/hints.ts
index 4a3cb2c..41dcd69 100644
--- a/packages/types/src/hints.ts
+++ b/packages/types/src/hints.ts
@@ -1,6 +1,6 @@
-import type { DeviceTiers, RenderingHints, RawSignals } from './profile.js';
+import type { DeviceTiers, RenderingHints, StoredSignals } from './profile.js';
 
-export function deriveHints(tiers: DeviceTiers, signals?: RawSignals): RenderingHints {
+export function deriveHints(tiers: DeviceTiers, signals?: StoredSignals): RenderingHints {
   const isLowEnd = tiers.cpu === 'low' || tiers.memory === 'low';
   const isSlowConnection = tiers.connection === '2g' || tiers.connection === '3g';
   const isBatteryConstrained =