Milestone 1: Add Numbers Zapier app, /v1/add, developer setup guide

packages/verae-activate is pushable with zapier-platform 19.1.0: local
Add Numbers (number1+number2=sum) needs no hosted API. zapier-platform
validate is clean (0 warnings). zappier POST /v1/add is a free metered
endpoint for the optional hosted path.

Tests: verae-activate 7/7, zappier 176/176, verae-zapier 5/5, middleware
gate 1 11/11. Morning steps: docs/04-activate/SETUP-ZAPIER-DEVELOPER.md

Learned: perform runs on Zapier cloud so arithmetic needs no public URL;
CLI and zapier-platform-core majors must match; do not mix zapier-sdk.

packages/zappier/openapi.yaml

@@ -58,6 +58,27 @@ paths:
       responses:
         '200':
           description: OK
+  /v1/add:
+    post:
+      operationId: add
+      summary: Add two numbers (activate-now sample)
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [number1, number2]
+              properties:
+                number1:
+                  type: number
+                  description: First addend
+                number2:
+                  type: number
+                  description: Second addend
+      responses:
+        '200':
+          description: OK
   /v1/usage:
     get:
       operationId: usage

packages/zappier/src/app.ts

@@ -157,6 +157,16 @@ export function buildApp(deps: AppDeps = {}): {
     res.json({ output: text.toUpperCase(), quote: res.locals.quote });
   });
 
+  app.post('/v1/add', meter('add', usage, pricing), (req, res) => {
+    const number1 = Number(req.body?.number1);
+    const number2 = Number(req.body?.number2);
+    if (!Number.isFinite(number1) || !Number.isFinite(number2)) {
+      res.status(400).json({ error: 'number1 and number2 must be finite numbers' });
+      return;
+    }
+    res.json({ number1, number2, sum: number1 + number2, quote: res.locals.quote });
+  });
+
   app.post('/v1/storage', parseMetadata, meter('storage', usage, pricing), (req, res) => {
     const metadata = res.locals.parsedMetadata as Record<string, unknown>;
     const files = (req.files as Express.Multer.File[]) ?? [];

packages/zappier/src/pricing.ts

@@ -63,6 +63,7 @@ export const DEFAULT_RATE_CARD: RateCard = {
     status: { kind: 'free' },
     'storage-list': { kind: 'free' },
     transform: { kind: 'fixed', fixedCents: 4 },
+    add: { kind: 'free' },
     storage: { kind: 'variable', baseCents: 10, perKbCents: 1, perMbCents: 50 },
   },
 };

packages/zappier/tests/app.test.ts

@@ -18,6 +18,25 @@ describe('Zappier API', () => {
     expect(res.body.quote.totalCents).toBe(0);
   });
 
+  it('POST /v1/add returns the sum and is free', async () => {
+    const { app } = buildApp();
+    const res = await request(app)
+      .post('/v1/add')
+      .set('x-api-key', KEY)
+      .send({ number1: 2, number2: 3 });
+    expect(res.status).toBe(200);
+    expect(res.body.sum).toBe(5);
+    expect(res.body.number1).toBe(2);
+    expect(res.body.number2).toBe(3);
+    expect(res.body.quote.totalCents).toBe(0);
+  });
+
+  it('POST /v1/add rejects missing fields', async () => {
+    const { app } = buildApp();
+    const res = await request(app).post('/v1/add').set('x-api-key', KEY).send({ number1: 1 });
+    expect(res.status).toBe(400);
+  });
+
   it('POST /v1/transform uppercases text at the multiplied fixed price', async () => {
     const { app } = buildApp();
     const res = await request(app)