Lesson 5.4 — Multi-Step Agents: Plan, Act, Check

Introduction to AI · Module 5: AI Agents · About 90 min · Windows PC, PowerShell 5, Claude Code (Max)

Goal: have an agent plan first, then turn a folder of receipts into a CSV plus a one-page summary, with 2 or fewer interventions from you.

Before you start

• cd $HOME\agent-night
• Interventions counter: write 0 here and add 1 each time you have to correct it:

Step 1 · Make 10 fake receipts (⏱ 0:00–0:10)

Paste the whole block:

mkdir receipts -Force | Out-Null
$data = @(
 "2026-10-01,Woolworths,Groceries,84.20",
 "2026-10-03,Shell,Fuel,71.50",
 "2026-10-05,Bunnings,Home,39.98",
 "2026-10-08,Coles,Groceries,62.15",
 "2026-10-10,Energex,Utilities,188.40",
 "2026-10-12,Chemist Warehouse,Health,23.99",
 "2026-10-15,Ampol,Fuel,68.00",
 "2026-10-18,Aldi,Groceries,45.60",
 "2026-10-21,Telstra,Utilities,89.00",
 "2026-10-24,Kmart,Home,27.50")
$i = 1
foreach ($d in $data) {
  $f = $d.Split(",")
  "RECEIPT`r`nStore: $($f[1])`r`nDate: $($f[0])`r`nItems: assorted`r`nTOTAL AUD `$$($f[3])" |
    Out-File ("receipts\r{0:D2}.txt" -f $i) -Encoding utf8
  $i++
}
(dir receipts).Count

You should see 10. Open one with notepad receipts\r01.txt to see what a receipt looks like.

• 10 receipts

Step 2 · Write the checker (⏱ 0:10–0:20)

@'
$ok = $true
if (-not (Test-Path out\receipts.csv)) { "missing out\receipts.csv"; $ok = $false }
else {
  $rows = @(Import-Csv out\receipts.csv)
  if ($rows.Count -ne 10) { "expected 10 rows, got $($rows.Count)"; $ok = $false }
  foreach ($c in "date","store","category","total") {
    if (-not ($rows[0].PSObject.Properties.Name -contains $c)) { "missing column $c"; $ok = $false } }
  $sum = ($rows | % { [double]$_.total } | Measure-Object -Sum).Sum
  if ([math]::Abs($sum - 700.32) -gt 0.01) { "total is $sum, expected 700.32"; $ok = $false }
}
if (-not (Test-Path out\summary.md)) { "missing out\summary.md"; $ok = $false }
if ($ok) { "PASS" } else { "FAIL" }
'@ | Out-File check-receipts.ps1 -Encoding utf8
.\check-receipts.ps1

You should see missing out\receipts.csv, missing out\summary.md and FAIL. Correct for now.

• Checker prints FAIL

Step 3 · Plan mode first (⏱ 0:20–0:35)

claude

Press Shift+Tab until the bottom of the screen says plan mode. Then type:

Read every file in receipts\. Create out\receipts.csv with columns
date,store,category,total (categories: Groceries, Fuel, Home, Utilities, Health)
and out\summary.md (one page: total spend, spend per category, biggest purchase,
one money tip). Then run .\check-receipts.ps1 and fix anything until it prints PASS.
Never edit or delete files in receipts\.

You should see a numbered plan. Read it. Is anything missing or wrong? If so, say so (that counts as 1 intervention).

• Plan read and approved

Step 4 · Let it execute (⏱ 0:35–1:05)

Approve the plan (choose the option to proceed). Watch the loop: read → write → check → fix. Approve tool use when asked. Approving doesn't count as an intervention; correcting it does.

When it reports PASS, leave Claude: **type /exit and press Enter. Wait until you see PS C:\...> before the next command.** Then confirm:

.\check-receipts.ps1
Import-Csv out\receipts.csv | Format-Table

You should see PASS and a 10-row table.

• PASS confirmed by you

Step 5 · Open in Excel and read the summary (⏱ 1:05–1:15)

start out\receipts.csv
notepad out\summary.md

You should see 10 rows in Excel, and a summary showing a total of $700.32 with the biggest purchase being Energex $188.40.

• Excel and summary look right

Step 6 · Reflect (⏱ 1:15–1:25)

• Interventions used: ____ (target ≤ 2)
• What did planning first change? ______________________

✅ Pass check

• .\check-receipts.ps1 prints PASS
• CSV opens in Excel with 10 correct rows; summary exists
• You intervened 2 times or fewer
• Told Skills Coach so 5.4 gets marked done

Troubleshooting