turntax

turntax

Coding agents re-send their instruction files with every turn. turntax measures that fixed per-turn cost for a repository, for every agent that reads it, and shows where to cut it.

npx turntax

Try it in the browser, with nothing uploaded: https://torutdev.github.io/turntax/ — drop a folder or enter a public GitHub repository. Links like https://torutdev.github.io/turntax/?repo=owner/name open straight to that repository's report.

State of agent instruction files: what turntax finds in 100 popular repositories, a new edition every month with pinned commits and the script to reproduce it (scripts/state-of.mjs).

Set up the GitHub Action and a config in one command:

npx turntax init

Supported agents

Each agent's documented loading rules decide what is sent on every turn, what loads only when the agent works in a folder or touches a matching file, and what is ignored.

Where an agent reads the same skill name from two folders, it is counted once, in the order the agent documents (or an assumed order, noted for that agent).

Agents that load exactly the same files share one row in the report (files loaded only as a /command, which cost nothing per turn, do not split a row):

always  o200k/turn  on-demand  model                tokens/turn  counted by                   100 turns  cached   agents

4 272 53 (no selected model) Claude Code 1 63 0 GPT-6.1 Sol 63 estimate (o200k_base proxy) $0.01 $0.0006 OpenAI Codex, Roo Code, Kiro, JetBrains Junie 1 17 0 (no selected model) Gemini CLI 5 311 59 GPT-6.1 Sol 311 estimate (o200k_base proxy) $0.06 $0.0031 Cursor 4 307 55 GPT-6.1 Sol 307 estimate (o200k_base proxy) $0.06 $0.0031 GitHub Copilot 2 75 0 GPT-6.1 Sol 75 estimate (o200k_base proxy) $0.01 $0.0008 Windsurf Cascade 2 21 32 GPT-6.1 Sol 21 estimate (o200k_base proxy) $0.0042 $0.0002 Cline 1 11 0 GPT-6.1 Sol 11 estimate (o200k_base proxy) $0.0022 $0.0001 Zed 3 84 32 GPT-6.1 Sol 84 estimate (o200k_base proxy) $0.02 $0.0008 Goose, OpenCode, Kilo Code 3 84 51 GPT-6.1 Sol 84 estimate (o200k_base proxy) $0.02 $0.0008 Amp 3 108 32 GPT-6.1 Sol 108 estimate (o200k_base proxy) $0.02 $0.0011 Warp 2 282 19 GPT-6.1 Sol 282 estimate (o200k_base proxy) $0.06 $0.0028 Factory Droid 4 303 51 GPT-6.1 Sol 303 estimate (o200k_base proxy) $0.06 $0.0030 Augment Code 1 63 0 (no selected model) Google Jules 7 330 69 GPT-6.1 Sol 330 estimate (o200k_base proxy) $0.07 $0.0033 Devin Local / Devin CLI

Advice (savings are estimates in o200k tokens per turn) HIGH duplicate CLAUDE.md, AGENTS.md [saves ~48 tokens/turn] 3 identical lines are loaded twice every turn by cursor, copilot, factory-droid, augment, devin. Keep them in one file. HIGH contradiction AGENTS.md, CLAUDE.md [saves ~11 tokens/turn] Conflicting package manager: "Always use npm for installs and scripts in this repository." (AGENTS.md:3) vs "Always use pnpm for installs and scripts in this repository." (CLAUDE.md:5). (Removing the outdated line.) MEDIUM scopable-section CLAUDE.md:12 [saves ~128 tokens/turn] Section "API package" is mostly about packages/api/. Move it to packages/api/AGENTS.md (or CLAUDE.md), a path-scoped rule, or an instructions file ...

(Excerpt of the output for test/fixtures/mixed with --models gpt-6.1-sol.)

What it counts, and how

Claude's tokenizer is not public, and Anthropic's docs note that newer Claude models produce noticeably more tokens than older ones for the same text. turntax never shows an OpenAI count as a Claude or Gemini number: without a key those rows say "needs API key". The o200k column is a labelled reference count for every file.

Cost per N turns = tokens per turn × N × input price. The "cached" column assumes every turn reads the context from the prompt cache. Prices come from a dated table with a source link per model (turntax --list-models); pass --prices my-prices.json to use your own.

See docs/how-it-counts.md for the loading rules per agent and their sources.

Advice

All checks are deterministic. Each one shows an estimated saving in o200k tokens per turn.

• duplicate: identical lines in two files. A per-turn saving only when one tool loads both; otherwise flagged as drift risk.
• contradiction: conflicting rules reaching the same agent (package manager, indentation, quotes, semicolons).
• scopable-section: a section mostly about one directory that could load only there (nested file, path-scoped rule, applyTo).
• oversized-section: a large always-loaded section that could become an on-demand skill.
• size-limit: documented limits (CLAUDE.md under 200 lines, Codex's 32 KiB cut-off, Windsurf's 12,000 characters per rule and 6,000 for global rules, Cursor's 500 lines, Factory's 80,000 characters, Augment's 49,512 characters).
• misconfigured: files a tool ignores, such as .md files in .cursor/rules or Windsurf rules without a trigger.
• stale-reference: referenced files or npm run scripts that no longer exist.
• non-english: non-English sections. The token multiplier is measured only against an English version you supply (--english CLAUDE.md=CLAUDE.en.md) or, if you opt in, a Claude translation (--translate).

Fixing

npx turntax --fix            # print a diff of the safe fixes; nothing is changed

npx turntax --fix --write # apply them

--fix handles four kinds of advice:

• duplicate: removes lines from a file when every agent that reads the file also reads the same lines every turn from another file. Skill, command and subagent files are left whole. A CLAUDE.md that repeats at least 80% of the lines of the AGENTS.md next to it, at least 3 of them full sentences, and every file it imports, keeps only its own lines and imports the rest with @AGENTS.md, as Claude Code's docs suggest; agents that read both stop paying for the copy, and the summary says how much any agent now reads on top.
• scopable-section: moves a section into the folder it is about: the same file name there (packages/api/CLAUDE.md), a nested AGENTS.md, or a Claude Code rule with paths:. The folder the section is about must already exist, and sections with @imports or relative links stay put. A section moves together with its subsections.
• oversized-section: moves a large procedure (a section of at least --section-tokens, 600 by default, whose heading names a release, deploy, setup or similar procedure, or that is mostly numbered steps; each subsection must pass too) into a new skill, .claude/skills/ /SKILL.md for Claude Code or .agents/skills/ /SKILL.md for Codex, and leaves the heading with a one-line pointer. Only the skill's name and description load every turn. Many agents now read one or both folders, but not all of them do (Zed reads only .agents/skills, for example), so by default this fix is often refused; --tools limits the check to the agents you use.
• misconfigured: renames .md files in .cursor/rules to .mdc.

Before a fix is kept, the files are classified again with the change applied: every agent must still read every line it read before, including files reached through @imports, and as often as before. The exceptions are moved text: a section moved into a folder may load only when the agent works there, and a procedure moved into a skill only when the skill is used. Otherwise the fix is skipped and the reason is printed. A moved section can reach agents that did not read it before (a nested AGENTS.md is read by more agents than a CLAUDE.md); the summary names them. By default that check covers every supported agent, so a section of AGENTS.md usually stays where it is, because some agents read only the root file. --tools codex,claude-code limits the check