Cursor's pstack adds a skill that has your agent formally verify the riskiest invariant in your repo

Calling /create-formal-verification-skill makes the agent pick a high-stakes property (races, retries, parsers, unsafe code), choose a tool such as TLA+, CBMC, or Kani, show the check failing on a deliberately broken variant, then leave a project-local skill so the next agent can rerun it with one command. pstack also ships into Claude Code's plugin marketplace from the same repo, and Cursor's own eval behind the skill is small (one run per repo on six open-source projects).