Gambit
Mutation Testing · Open Source · Certora
Smart contract specs have blind spots. I designed a tool to find them.
The Coverage Map: showing 45% coverage with 7 caught and 8 uncaught mutations.
What is Mutation Testing?
Gambit is an open-source tool developed by Certora. It intentionally introduces small "patches" or bugs into a smart contract to see if your security rules are strong enough to catch them.
If a rule identifies the bug, the mutant is "killed." If not, it "survives," signaling a gap in your security coverage.
Data without clarity.
The original output was a confusing matrix of rules and mutants. It was nearly impossible to tell which rules were effective, which mutants were slipping through, or where rules were simply redundant.
A simple table couldn't reveal the patterns or gaps that a developer needs to see to improve their specs.
The Coverage Map
I realized that if a rule catches a mutant, they should share the same visual space.
I used circle containment to show these relationships. Mutant bubbles sit inside the rule rings that caught them. Overlapping rings show where multiple rules caught the same bug, while floating bubbles represent uncaught mutants that need attention.
By using green for effective rules and yellow for those that caught nothing, the health of an entire specification becomes clear in seconds.
This was an original design concept rather than a pre-defined requirement.
Open-Source Success
Gambit launched as an open-source MVP, and the Coverage Map became its standout feature. It turned an abstract data problem into a visual tool that any developer can understand instantly.