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.
---
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.
effort: low
---
# 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](https://github.com/rtk-ai/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
… install to load the full skill