Claude Code agent set Meta Ads budget 100x wrong — caused NT$11,168 (USD ~$350) financial loss

Summary

Claude Code (Opus) acting as an ad operations agent set a Meta Ads campaign daily budget to NT$30,000 instead of NT$300 (100x error) via the Meta Ads MCP tool (ads_create_campaign or ads_update_entity). The campaign ran for ~2 days before the user noticed multiple NT$900 billing charges and flagged it.

When the user flagged the issue, Claude spent additional time querying data and debating whether the API values were in cents vs full dollars — instead of immediately pausing the campaign. This delay caused further unnecessary spend.

Financial Damage

| Item | Amount |
|------|--------|
| Intended daily budget | NT$300/day |
| Actual daily budget set | NT$30,000/day |
| Total spend | NT$11,768 |
| Expected spend (~2 days) | ~NT$600 |
| Overspend (loss) | ~NT$11,168 (~USD $350) |

What happened

1. Claude Code agent created Meta Ads campaign "NXLV Kai UGC — ATC Optimize v1" with daily_budget: 30000
2. For TWD (Taiwan Dollar) accounts, Meta API uses full dollar values, NOT cents — so 30000 = NT$30,000
3. Claude incorrectly assumed the value was in cents (as some currencies use)
4. Campaign ran at 100x intended budget
5. User noticed NT$900 recurring charges on 2026-05-26 morning and asked Claude to check
6. Claude pulled the data, saw "NT$30,000/day" budget, and told the user it was probably cents = NT$300 ← wrong
7. User corrected Claude: "it's not 30000/day. it's 300/day"
8. Claude then debated instead of immediately pausing
9. Campaign was eventually paused but ~NT$11,168 was already lost
10. Meta reported 8 purchases but only 1 real order went through (Cyberbiz verified)

Root cause

• No unit verification when setting Meta Ads budget via API for TWD currency
• No read-back confirmation after budget was set
• When user flagged a spend problem, agent prioritized investigation over immediate action (should have paused first)

Environment

• Claude Code CLI on macOS
• Model: claude-opus-4-7
• Meta Ads MCP integration (claude.ai connected tools)
• Ad account currency: TWD (Taiwan Dollar)
• Ad account ID: act_1681570026314651

Request

The user is requesting Anthropic consider reimbursement for the ~NT$11,168 (~USD $350) overspend caused directly by Claude Code's incorrect budget setting and delayed response.

Date

2026-05-25 to 2026-05-26