rtk-improved AGENTS.md

Instructions for RTK, a command-line tool that shortens noisy shell output before it reaches the assistant. They explain when to compress repetitive output and when exact details must be preserved.

In plain words
What is it for?
Use them when running directory listings, Git commands, Docker commands, package lists, or large test and build runs in a coding project.
Why use it?
They reduce unnecessary context while preventing important information, such as patches, structured data, or small outputs, from being hidden.

Instructions file for CodexOpenCode

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/coding-dev-tools/rtk-improved/agents-md
Clone the repo
git clone --depth 1 https://github.com/Coding-Dev-Tools/rtk-improved

Made for: Codex, OpenCode.

Per session 725 This file is loaded in full into every session.
When invoked 725 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00725 $0.00725
Opus 5 $0.00362 $0.00362
Sonnet 5 $0.00145 $0.00145
Haiku 4.5 $0.00072 $0.00072

Measured yesterday against content hash ba8c32257566, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rtk-improved AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

AGENTS.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

RTK Token Optimization

RTK (Rust Token Killer) compresses shell command output before it enters the context window. Used well it cuts tokens on noisy commands and sharpens context (less noise → better reasoning). Used badly — compressing output you actually needed — it hides detail and forces re-runs that cost more than they save. These rules keep it net-positive.

Setup

RTK is optional. If rtk --version fails or rtk isn't on PATH, run commands normally — never block work to install it.

The one rule: compress noise, preserve signal

Use rtk <cmd> when output is large, repetitive, low-stakes — skim, not study: rtk ls, rtk git status, rtk git log, rtk docker ps, rtk pip list, and big test/build runs (rtk cargo test, or rtk err <cmd> — RTK keeps the failures and drops the green).

Run the command raw (no rtk) when you need every character:

  • a diff/patch you'll apply, or a hunk you'll edit — exact bytes and line numbers matter
  • structured output you'll parse — JSON, --format=…, anything piped into another tool
  • small output (≲30 lines) — nothing to save, and real risk of dropping the one line you need
  • secrets / exact config — never reason about a lossy view of these
  • a file you intend to edit — use the native Read tool (lossless; it bypasses RTK anyway)

When unsure, start raw. Lean context comes from cutting noise, not signal.

Never default to lossy modes

Plain rtk <cmd> keeps the signal — errors, diffs, stack traces, exit codes — and strips only noise. --ultra-compact, rtk read … -l aggressive, and rtk smart (2-line summary) are lossy — opt-in only for skimming something huge and unimportant, never your default. (RTK's own docs still mention a -u short form for --ultra-compact; it was removed upstream and doesn't work — use the long flag.)

Harness safety — don't let it break the tool call

  • Don't wrap streaming/follow output (-f, tail -f, a growing log): RTK buffers output to filter it, so it can hang the command. Run these raw.
  • When a pass/fail verdict matters (tests, CI gates), trust the command's raw exit code. If you can't tell whether the rtk view preserved it, re-run raw or use rtk proxy <cmd>.
  • Prefer the native file/search tools over rtk ls/grep/find/read — they're lossless, give line numbers, and don't pass through RTK anyway.

Read the full file on GitHub · 60 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 60 lines · 725 tokens per session scan A ba8c32257566

Subscribe to this mod's changes

rtk-improved AGENTS.md is an instructions file published in the GitHub repository Coding-Dev-Tools/rtk-improved (10 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 725 tokens to every session, about $0.0036 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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