A Small Mistake, A Big Lesson
Last week, while validating complex formulas in a Google Sheet using Claude Code on our Windows device, something unexpected happened. We expected it to catch every error, but reality was a bit different.
Claude Code partially missed a nested IF function structure. On the surface it looked fine, but certain conditions caused values to slip through. At first, we were frustrated. 「Can't AI handle this much?」 we thought.
Treating Errors as Insights
But when our small team reviewed the issue together, a clear pattern emerged. The parts Claude Code missed were always the same type: 「nested function chains of 3+ layers with dynamically changing reference ranges.」
Once we spotted this, we tried a different approach.
Claude Code excels at structural validation,
we excel at spotting logical boundaries,
what happens when we combine both?
Adding a New Automation Layer
Here's what we built:
1. **First Check (Claude Code)** , Syntax, range errors, basic logic
2. **Second Check (Human-defined rules)** , Auto-flag nested functions 3+ levels deep
3. **Third Check (Sample data testing)** , Run with real values
Understanding AI's blindspots became the moment we could design automation to complement them.
What Our Small Team Learned
As non-developers, this is exactly what we can do. Acknowledge tool limitations, pinpoint where those boundaries lie, and design processes to fill the gaps. Perfect automation doesn't exist, but automation learned from failure is far more resilient.
Next time Claude Code misses something, we'll ask differently now: 「What can we learn this time?」