Exit Code Fast Checking (Zero-Stdout Verification Protocol)

Overview

When an agent runs a build tool, type-checker, or test suite (tsc --noEmit, cargo build, npm run lint), successful runs generate 100 to 800 lines of informational progress logs ("Compiling 140 modules...", "Emitting chunks...", "Done in 2.4s").

Ingesting hundreds of lines of successful build output burns 1,000+ context tokens without providing any new actionable information to the model.

The Zero-Stdout Exit Code Protocol intercepts subprocess execution: if the Exit Code is 0 (Success), stdout is suppressed and replaced with a compact 1-line confirmation token ([OK: exit 0]). Full output is streamed only when the exit code is non-zero (Failure).

Verbose Success Logs vs. Exit Code Confirmation