Developers Face 'Interop Tax' as AI Coding Tools Use Incompatible Config Formats

AI coding assistants like Claude, Codex, and Gemini each use their own proprietary configuration file formats, meaning skills or tool definitions built for one agent are invisible to others. This fragmentation forces developers to manually re-wire the same capabilities for every platform they work with, a burden the author calls the 'interop tax.' The core issue is that while all major agent tools have independently converged on storing behavior as files in a repository, they use conflicting naming conventions and schemas. A proposed solution involves separating a tool's contract — its name, inputs, outputs, and permissions — from its implementation, making capabilities portable across runtimes. The author argues this separation, modeled on OS-style layered design, would allow any agent to read and execute the same capability without duplication.