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phx-mix-compression

Installs rtk filters that compress verbose mix command output before it reaches the transcript.

537|38|Updated Feb 12, 2026
Search Tags:#context optimization#Elixir#mix#Phoenix#token compression#RTK#cli filtering
One-click install
npx skills add https://github.com/oliver-kriska/claude-elixir-phoenix --skill phx-mix-compression
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: phx-mix-compression
Source: https://github.com/oliver-kriska/claude-elixir-phoenix/tree/main/targets/codex/skills/phx-mix-compression
Command: npx skills add https://github.com/oliver-kriska/claude-elixir-phoenix --skill phx-mix-compression

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires rtk, and includes references (resource) components.

What problem does it solve?

Mix commands like mix test, mix credo, and mix dialyzer emit verbose, repetitive output that floods the AI conversation transcript and consumes context tokens fast. This Skill installs rtk, a CLI proxy that filters mix output at the subprocess layer before it lands in the transcript, reducing token usage by 5-15% on mix-heavy workflows.

Core Features & Use Cases

  • Bundled filter set: Ships six production-tested TOML filters covering mix test, mix credo, mix dialyzer, mix deps.get, mix ecto.migrate, and mix compile, plus Ash codegen and migrate variants.
  • Signal preservation: Short-circuits happy paths to one-liners (e.g., "mix test: all pass") while preserving compile errors, test failures, dialyzer warnings, and stack traces with file:line references.
  • Verification workflow: Runs rtk verify against embedded test fixtures to confirm filters work, and merges rather than overwrites existing .rtk/filters.toml files.
  • Use Case: During a long debugging session where mix compile and mix test run repeatedly, install these filters so passing runs collapse to single lines while failures remain fully visible.

Quick Start

Ask the AI to install rtk and set up mix output compression filters for this Phoenix project, then verify the filters pass.

Frequently Asked Questions about phx-mix-compression

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I reduce mix test output noise in Claude Code sessions?▼

Install rtk, a CLI proxy that filters mix output at the subprocess layer before it reaches the transcript. Copy the bundled filters to .rtk/filters.toml, run rtk init to install the shell hook, and passing test runs collapse to a single line while failures stay intact.

What is rtk and how does it compress CLI output?▼

rtk (Rust Token Killer) is a CLI proxy that intercepts terminal commands, runs them, and filters output through TOML regex rules before returning results. Its shell hook transparently rewrites mix X to rtk mix X, so filtering happens without manual prefixing.

Does rtk filtering hide compile errors or test failures?▼

No. The filters are designed to never strip critical signals: compile errors, test failure blocks, dialyzer warnings, and stack traces with file:line references pass through unchanged. Only progress noise and happy-path output get collapsed.

Why do rtk filter test fixtures fail after copying?▼

Fixture failures usually mean regex patterns do not match your rtk version's regex engine. rtk uses Rust's regex crate, which does not support backreferences like \1 or \2, so custom patterns using them will silently fail.

Can I bypass rtk filtering for a single mix command?▼

Yes. Prefix the command with the shell builtin command, for example command mix test, to bypass the rtk hook and see raw unfiltered output for that invocation.

Does rtk send my command output to external servers?▼

No. rtk has telemetry disabled by default, with enabled = false in its config.toml. All filters run locally and no command output, file paths, or filter content leaves your machine.

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