Mix Output Compression

Mix commands (mix test, mix credo, mix dialyzer, mix compile) emit verbose, repetitive output that consumes context fast. This skill installs rtk — a CLI proxy that filters tool output before it lands in the transcript.

The filters short-circuit happy paths to a single line (mix test: all pass) while preserving full failure blocks, compile errors, and stack traces. Net win: 5-15% per-session token reduction on mix-heavy workflows.

When to use

• Long sessions — /phx:work or /phx:full hitting context limits from mix output
• Debugging loops — /phx:investigate retrying mix compile/mix test repeatedly
• Dialyzer-heavy projects — mix dialyzer output dominates the transcript

Iron Laws