Using TLA+ and state diagrams to catch boundary bugs in coding agents

On November 9, 2026 at 23:08, DEV Community published "Using TLA+ and Statecharts to Catch Edge-Case Bugs in Coding Agents Early". The piece looks at how to combine TLA+ and statecharts when working with coding agents such as Claude Code, in order to catch boundary bugs hiding in implicit logic flows during the implementation phase. The author notes that when you write code with a Coding Agent (Claude Code in this case), the normal practice is to write unit, integration and end-to-end tests so that later feature work, bug fixes or refactors do not change the application's current behavior. That approach, however, does not address edge-case bugs: limited by domain logic, such defects tend to surface only once they occur in the production environment, when developers treat them as bugs and attempt to fix them. The proposed remedy is to abstract application logic into a state machine, which helps the agent pinpoint edge scenarios that conventional unit tests struggle to cover. Based on the material available, the article only introduces this idea. The source excerpt cuts off mid-sentence, and no concrete TLA+ specification or statechart example, follow-up work or subsequent developments are included.