phx-mix-compression
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.
npx skills add oliver-kriska/claude-elixir-phoenix --skill phx-mix-compression --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# 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 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 3.
- When to use
- Iron Laws
- Workflow
- Step 1: Detect rtk
- Step 2: Seed .rtk/filters.toml
- Step 3: Verify filters work
- Step 4: Confirm shell hook
- Customization
- What this is NOT
- References
which rtk && rtk --version mkdir -p .rtk cp "references/rtk-filters.toml" .rtk/filters.toml rtk verify # runs all embedded [[tests.*]] fixtures rtk verify --filter mix-test # one filter only
What does the phx-mix-compression skill do?
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.
How do I install it?
Run `npx skills add oliver-kriska/claude-elixir-phoenix --skill phx-mix-compression --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From oliver-kriska/claude-elixir-phoenix, a repository with 515 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.