Tusk is a YC W24-backed AI agent that automatically generates unit and integration tests for your pull requests. Founded by Marcel Tan and Sohil Kshirsagar, UC Berkeley classmates with engineering and PM experience at companies like 6sense and Aspire, Tusk tackles what might be the most universally dreaded task in software engineering: writing tests. The platform sits in your CI pipeline as a non-blocking check and suggests happy path and edge case tests that are not covered by your existing test suite, using full codebase context and business logic to generate relevant, executable test cases.
The core differentiator is Tusk's use of live production traffic to generate tests. Version 2.0, launched in February 2026, turns your actual app traffic into unit and API tests, meaning test cases reflect real-world user behavior rather than hypothetical scenarios. This traffic-to-test approach catches regressions that purely code-analysis-based tools miss because it grounds tests in how users actually interact with your application. Tusk reports catching real-world regressions in 43% of PRs — a number that reflects genuine bug prevention, not just coverage padding.
The agent is self-iterating. When Tusk generates tests, it runs them in an ephemeral sandbox and automatically fixes any errors it encounters. There is no back-and-forth with an AI copilot required. This is a critical distinction from code review tools that leave vague comments about missing tests — Tusk actually writes the tests, runs them, verifies they pass, and presents you with executable results. You review the generated test cases and commit them to your branch with one click, or raise a separate PR. The 69% incorporation rate for generated test suites suggests the quality is high enough for production use.
Customization puts engineers in control. Teams can configure Tusk to match their testing guidelines — how to mock, which factories to use, directories to avoid, and framework-specific conventions. The agent automatically maintains existing test suites on every commit, updating them to reflect the latest business logic. This maintenance capability alone saves significant engineering time, as keeping tests current with evolving code is often more burdensome than writing them in the first place.
Integration coverage spans the major development tools. Tusk works with GitHub for version control, and connects with Jira, Linear, Notion, and GitHub Issues for ticket context. The platform also integrates with Figma, Loom, and Jam for pulling visual and bug report context into test generation. CI/CD integration means Tusk runs automatically on every PR, requiring no manual triggering or workflow changes from developers.
Customer results are concrete. One team went from 2,500 tests to over 7,000 in a month using Tusk for their core evals functionality. Another credits Tusk with contributing roughly three-quarters of their recent test coverage increase on a legacy codebase. DeepLearning.AI's senior backend engineer specifically highlights Tusk's ability to protect against edge case threats that manual testing often misses. These are not theoretical benefits — they represent measurable improvements in test coverage and regression prevention.