What it does
Read the two properties F5 publishes for every attack signature in F5 AWAF - Advanced WAF (formerly BIG-IP ASM - Application Security Manager): its Accuracy and its Risk. Add whether the signature even applies to your systems and whether it is enforced, and the tool tells you how false-positive-prone the signature is, how much damage a real match would do, and the tuning move that follows. It is deterministic and runs entirely in your browser.
Why properties, not a signature-ID lookup
F5's signature set is proprietary and enormous, so a per-ID database would be neither feasible nor honest. But F5 documents what Accuracy and Risk mean for every signature, and those two properties are what actually drive false-positive tuning, so the tool works from them. You read Accuracy, Risk, and Systems straight from the signature's own entry in the policy.
Accuracy is false-positive susceptibility
F5 defines accuracy as a signature's ability to identify the attack, including its susceptibility to false-positive alarms, and states plainly that higher accuracy results in fewer false positives. So a Low accuracy signature has a high likelihood of false positives, Medium has some, and High has a low likelihood. Risk is a separate axis: the potential damage if the attack succeeds, from reconnaissance (Low) to sensitive-data exposure or moderate damage (Medium) to full system compromise or denial of service (High).
The accuracy-by-risk quadrant
The tool places the signature in a 2x2. Low accuracy plus low risk is the prime relax candidate: frequent false positives, little lost by relaxing. Low accuracy plus high risk is false-positive-prone but dangerous, so you investigate the actual request before disabling rather than waving a possible real attack through. High accuracy plus high risk is a reliable, high-stakes block you do not relax. High accuracy plus low risk is reliable but low-stakes. It also flags a signature that targets a system your application does not run as pure noise, and surfaces accuracy as a lever: because accuracy is a signature-set filter criterion, a set weighted toward higher-accuracy signatures produces fewer false positives.
Grounding
The accuracy and risk definitions come from F5's Working with Attack Signatures documentation and the classic BIG-IP ASM attack-signature reference (which spells out the low, medium, and high false-positive likelihood and signature-set scoping by system and accuracy), plus K70544352 on reducing false positives. Nothing you select is uploaded or leaves the page.