Invoice check

Checks an invoice against what was agreed and flags anything off.

Operations · produces a Review · built in, ready to run

What you give it

Something like this:

Invoice INV-2291, Zenith Software Services, dated 2026-02-31
Agreed in contract: 40 hours development @ PKR 6,000/hr, one-time setup PKR 50,000, payment 30 days.

Lines:
1. Development 44 hrs @ 6,000 = 264,000
2. Setup fee = 50,000
3. Project management 8 hrs @ 6,000 = 48,000
4. Urgent delivery surcharge = 25,000
Subtotal: 377,000
GST 17% = 66,470
Total: 453,470
Terms: payment due on receipt

What you get back

This is a real run of the skill on the input above, not a mock-up:

## **INVOICE AUDIT – INV-2291, ZENITH SOFTWARE SERVICES**

### **Problems Found (ranked by cost impact):**

1. **Invalid invoice date: 2026-02-31**
   - February has maximum 28 days (29 in leap years)
   - **What it should be:** A valid date in February 2026 (e.g., 2026-02-28)
   - **Impact:** Invoice is technically undated/invalid

2. **Development hours exceed contract (most costly)**
   - **What's wrong:** Invoice shows 44 hours @ PKR 6,000 = PKR 264,000
   - **What should be:** Contract specifies 40 hours @ PKR 6,000 = PKR 240,000
   - **Difference:** +PKR 24,000 (overcharge)

3. **Project management line not in contract**
   - **What's wrong:** 8 hrs @ 6,000 = PKR 48,000 charged
   - **What should be:** PKR 0 (no project management mentioned in contract)
   - **Difference:** –PKR 48,000 (unauthorised charge)

4. **Urgent delivery surcharge not in contract**
   - **What's wrong:** PKR 25,000 charged
   - **What should be:** PKR 0 (no urgent surcharge in contract)
   - **Difference:** –PKR 25,000 (unauthorised charge)

5. **Payment terms conflict**
   - **What's wrong:** Invoice states "payment due on receipt"
   - **What should be:** Contract specifies 30 days net
   - **Impact:** Shortens payment window by 30 days

### **Corrected Invoice (per contract):**
- Development: 40 hrs @ 6,000 = 240,000
- Setup fee: 50,000
- **Subtotal: 290,000**
- GST 17%: 49,300
- **Correct Total: 339,300**

### **Net Overcharge: PKR 114,170** (current invoice PKR 453,470 vs. contracted PKR 339,300)

The wording changes a little every run. The shape does not — that is what the procedure below is for.

Tools it uses

None of its own. A skill that only writes needs no tools, so this one inherits whatever your assistant can normally reach.

The procedure it follows

This is the skill, in full. Add it to your own skills to change any of it.

Check the invoice below.

Verify: the arithmetic, that every line was actually agreed, the tax treatment, the dates, and the payment terms.

Report only problems, most costly first: what is wrong, what it should be, and the difference in money. If everything checks out, say so in one line.

How to run it

In chat, on the Skills page and in automations you do not have to add it first — a library skill runs as it is. Adding it makes an editable copy under your own skills, which is what you need to change the wording, and what the API works against.

New to skills? Start with what a skill is.