Coding Agents Don’t Need Bigger Context Windows — They Need a Context Compiler

in pure Python. Before sending anything to the model, it figures out what your target file actually depends on, trims non-essential code down to pure interfaces, and drops everything unreachable. Tested it on two real Python repos: it cut prompt sizes by 69–74% and ran in under 75 ms. All the numbers below are pulled straight from captured terminal runs. If the tool couldn’t determine something with certainty, it explicitly marked it instead of guessing. Compilers are just filters that know what to keep. You give one an entry point and a codebase, it traces what actually gets called, throws out the dead weight, and outputs an intermediate representation with only the detail the next step needs. Nothing extra. Most coding agents don’t treat prompt construction like a compiler. They build some form of repository map, gather files they believe are relevant, and send them to the model with relatively little structural reduction. Larger context windows help, but they don’t remove irrelevant context. That extra context competes for attention with the code that actually matters. And when window sizes shrink, that bloat triggers compaction. Compaction sounds like routine cleanup until it happens mid-task: the agent summarizes its own context to…