--- title: "Turn your agent into a fraud detective" slug: fraud-detective-agent url: https://bankbridge.money/guides/fraud-detective-agent category: use-case published: 2026-04-23 updated: 2026-04-23 --- # Turn your agent into a fraud detective > Once a week, ask your agent to scan the last seven days of transactions for anything that doesn't fit your pattern: unfamiliar merchants, unusual amounts, transactions from unfamiliar locations (based on merchant names), or duplicate charges from the same vendor. It's not a replacement for your bank's fraud team, but it consistently catches things before the bank does. Fraud Detective Agent | BankBridge | BankBridge [Use case](/guides/use-cases) # Turn your agent into a fraud detective Updated Apr 23, 2026·4 min read Once a week, ask your agent to scan the last seven days of transactions for anything that doesn't fit your pattern: unfamiliar merchants, unusual amounts, transactions from unfamiliar locations (based on merchant names), or duplicate charges from the same vendor. It's not a replacement for your bank's fraud team, but it consistently catches things before the bank does. ## Why your agent beats the bank at this Bank fraud algorithms look at cohort behavior: is this transaction unusual compared to other customers' patterns? Your agent looks at your behavior specifically: is this transaction unusual compared to _your_ past transactions? The agent loses on speed (it doesn't run until you ask) but wins on specificity. Your bank will miss a fraudulent $30 charge at a coffee shop because that amount is common. Your agent knows you don't buy coffee in that city. ## The weekly prompt > “Scan my transactions from the last 7 days. Flag anything that: (1) comes from a merchant I haven't used before, (2) is an unusual amount for a merchant I do use, (3) looks like a duplicate charge from the same vendor within a day, or (4) is from a location that doesn't match my other recent activity. Use your judgment.” The agent calls `list_transactions` for the 7-day window, then compares against its baseline understanding of your spending from the 6-month context it built up during earlier tool calls in the session. If there's nothing suspicious, it says so. If there is, it surfaces each flag with context on why. ## What it reliably catches - Duplicate charges from a vendor within 24 hours (the classic “card was swiped twice” error). - Brand-new merchants you've never transacted with before. - A $300 charge at a merchant where you usually spend $30 (or vice versa). - Small “test charges” (<$5) that sometimes precede fraud — someone testing a stolen card. - A concentration of new charges in a short time window (card compromise in progress). ## What it doesn’t catch - **Highly sophisticated fraud** that mimics your patterns (rare for consumers, more common for business cards). - **Fraud on cards you haven't connected.** Obviously. But if you have multiple cards, this is a good prompt to connect them all. - **Transaction authorization after the fact.** The agent can only see posted transactions; pending ones sometimes show up late depending on the aggregator. - **ACH fraud** sometimes, because ACH descriptors are especially hard to pattern-match. ## Make it a Friday habit Sunday evening or Friday afternoon, whichever fits your routine. Claude Code users can save the prompt as `/fraud-detective` (one of the six skills in our [public skills repo](https://github.com/bankbridge-money/bankbridge-skills)). Other hosts: save to your agent's snippet system and trigger weekly. If the agent ever flags something real, you'll save yourself a week of back-and-forth with your bank. If it never does, five minutes of peace of mind. ## FAQ Can the agent dispute a charge for me? No. BankBridge is read-only, and dispute flows are bank-specific anyway. The agent tells you what looks suspicious and where; you go to your bank's app or website to file the dispute. What if the agent flags something legitimate? Happens sometimes. The first time you use a new service or travel to a new city, the agent might flag it. That's fine — it's a sanity check, not a blocking filter. You confirm it's real and move on. How far back should I ask it to look? Weekly review with a 7-day window is the sweet spot. Too short (1-2 days) and the agent doesn't have pattern context; too long (30 days) and genuine fraud has time to compound. Seven days matches most banks' dispute-filing windows. ## FAQ ### Can the agent dispute a charge for me? No. BankBridge is read-only, and dispute flows are bank-specific anyway. The agent tells you what looks suspicious and where; you go to your bank's app or website to file the dispute. ### What if the agent flags something legitimate? Happens sometimes. The first time you use a new service or travel to a new city, the agent might flag it. That's fine — it's a sanity check, not a blocking filter. You confirm it's real and move on. ### How far back should I ask it to look? Weekly review with a 7-day window is the sweet spot. Too short (1-2 days) and the agent doesn't have pattern context; too long (30 days) and genuine fraud has time to compound. Seven days matches most banks' dispute-filing windows.