The problem
Claude can build you a budget forecast, a financial model, a long document, a data analysis. But it can also make mistakes. Wrong formulas. Numbers that don't add up. Assumptions it made without telling you.
Most people just trust the output and send it. That's how errors end up in front of your boss or your client.
The fix
After Claude finishes something complex, you launch a second agent. This agent doesn't create anything. Its only job is to audit what the first one built. Check every number. Verify every formula. Flag anything that looks off.
One agent builds. One agent checks. You end up with something you can actually trust.
Step by step
How to do it
Step 1: Have Claude build the thing
Use Cowork or a chat to have Claude create whatever you need. A budget forecast, a report, a spreadsheet, a proposal. Let it finish completely.
Step 2: Start a new task
Don't ask the same session to check its own work. Start a fresh Cowork task or a new chat. Point it at the file Claude just created.
Step 3: Drop in the audit prompt
Give the second agent the audit prompt below. It reviews the file, checks for errors, and saves a summary of everything it found.
The prompt
Audit prompt (copy and paste into a new task)
You are a senior auditor. Your job is to review the file I'm about to give you and find every error, inconsistency, or problem. You are not creating anything new. You are only checking what was already built. Review this file and check for: 1. Any numbers that don't add up (totals, subtotals, percentages) 2. Formulas that reference the wrong cells or produce incorrect results 3. Assumptions that were made but not stated 4. Data that looks wrong, missing, or inconsistent 5. Formatting issues that would look unprofessional 6. Anything that contradicts itself For every issue you find: - What the error is - Where it is (cell, section, paragraph) - What the correct value or fix should be If you find nothing wrong, say so. Don't make up problems. Save your audit summary as a separate file next to the original.
Works for more than just spreadsheets
You can use this same approach for anything Claude builds:
Budget or financial model
"Act as a financial auditor. Check every formula, verify all totals match, and flag any assumptions."
Long report or proposal
"Act as an editor. Check for factual consistency, contradictions between sections, and any claims without evidence."
Client-facing email or document
"Act as a proofreader. Check for tone, accuracy, anything that could be misread, and any details that don't match what the client asked for."
Data analysis
"Act as a data reviewer. Verify the methodology, check for sampling errors, and make sure the conclusions actually match the data."
The rule is simple: if you wouldn't send it without double-checking it yourself, have a second agent check it first. It takes 30 seconds to launch and catches things you'd miss.
Want the full system?
Master AI by Monday
This is one workflow. The Weekend Claude Bootcamp sets up an entire system for your specific job. Projects, workflows, Skills, prompts, and a routine you'll use every week. 25 roles to choose from. Done in 2 hours.