phx-mix-compression

name	phx-mix-compression
description	Reduce mix output noise (5-15% token savings) by installing rtk filters that compress mix test/credo/dialyzer/compile output before it reaches Claude. Use when long mix output floods context.

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

1. NEVER strip critical signals — compile errors (** (CompileError), == Compilation error in), test failures (FAILURES, 0 failures — preserved even on short-circuit), dialyzer warnings, and stack traces with file:line MUST pass through unchanged
2. Verify after install — run rtk verify (or rtk verify --filter mix-test) to confirm the bundled test fixtures pass before declaring success