Borrowing it
Nothing to install: this file belongs to ikraamg/csstruth. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/ikraamg/csstruth/main/CLAUDE.mdgit clone --depth 1 https://github.com/ikraamg/csstruthWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/ikraamg/csstruth/claude-md)<a href="https://agentmods.dev/instructions/ikraamg/csstruth/claude-md"><img src="https://agentmods.dev/badge/instructions/ikraamg/csstruth/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/ikraamg/csstruth/claude-md"><img src="https://agentmods.dev/badge/instructions/ikraamg/csstruth/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.02060 | $0.02060 |
| Opus 5.5 | $0.00824 | $0.00824 |
| Sonnet 5.5 | $0.00412 | $0.00412 |
| Haiku 4.5 | $0.00206 | $0.00206 |
Grade A, and why
csstruth CLAUDE.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 1mo ago.
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.
How it starts
The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.
csstruth — Agent Context
Hard ground truth for CSS: extracts the browser's actual rendered layout as deterministic, diffable text so agents stop guessing. Chromium-only, via the Chrome DevTools Protocol. Public (MIT): github.com/ikraamg/csstruth · npm: csstruth.
Architecture (learn this first)
- One core, two skins. All logic lives in
src/core/*.src/cli.tsandsrc/mcp.tsare thin wrappers that call identical core functions. Never put logic in a skin — if both skins need it, it goes in core. - The seam is
withPage(url, fn, opts)insrc/core/connect.ts: opens a page, sets viewport, navigates, settles, runsfn, always tears down. Almost everything flows through it. Opts compose (captureAnimations,beforeNavigate,skipSettle) — mirror that pattern for new connection concerns. - The LayoutTree (
tree.ts) is the core representation: one line per element, byte-identical across runs. Determinism is the whole thesis — never add timestamps, key-order dependence, or randomness to rendered output. - 12 CLI commands (10 also MCP tools;
watchis CLI-only). Core modules: connect, extract, tree, invariants, explain, inspect, snapshot, verify, matrix, baseline, interact, animate, stability, state, fix, blame, watch, serve.
The invariant checks (src/core/invariants.ts)
Six rules power check/verify, each tuned so a violation is a REAL bug —
the exemptions are deliberate, not laziness, and each is tagged field #N /
NEXT-* in a comment (grep them for the rationale):
- viewport-overflow — content wider than the viewport.
- parent-bleed — a child past its container's padding box, BOTH axes
(
checkBleedmirrors horizontal/vertical, clamped by the nearest overflow-x/y). Exempts absolute/fixed and deliberately-displaced children (displaced(): negative margin, a translating transform viatranslatesBox—translateZ(0)and other no-op transforms still flag — or non-static position with a real inset). - zero-size / off-screen — interactive element with a 0 dimension or parked off-screen (unless inside a scroll/clip ancestor).
- text-clip — text past a hidden-overflow box with no ellipsis opt-in.
- overlap — two un-layered siblings overlapping. Exempts SVG internals,
sr-only, empty async placeholders (
isPlaceholderOverlap), and a descendant that escaped an intermediate container and lapped a cousin (escapesIntermediateContainer— parent-bleed owns that defect). - tap-target — sub-24px interactive element, flagged only when CROWDED
(WCAG 2.5.8 spacing:
crowded()centres a 24px circle on it and checks it clears every adjacent target — a lone or well-spaced small target is exempt). Measures an input's<label>not the sr-only input; also exempts a text link inline in a sentence (its own text + display:inline + real parent text — an icon-only link still flags).
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.
- 1mo ago Changed · +2 lines · +43 tokens per session 691f7a2ceac1
- 2mo ago First seen · 132 lines · 2,017 tokens per session scan A 563114a8f71e
csstruth CLAUDE.md is an instructions file published in the GitHub repository ikraamg/csstruth (2 stars, last pushed 1mo ago), licensed MIT. It adds 2,060 tokens to every session, about $0.0082 per session on Opus 5.5. 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.