Borrowing it
Nothing to install: this file belongs to Y0lan/laws-of-software-engineering. 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/Y0lan/laws-of-software-engineering/main/CLAUDE.mdgit clone --depth 1 https://github.com/Y0lan/laws-of-software-engineeringWrote 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/y0lan/laws-of-software-engineering/claude-md)<a href="https://agentmods.dev/instructions/y0lan/laws-of-software-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/y0lan/laws-of-software-engineering/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/y0lan/laws-of-software-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/y0lan/laws-of-software-engineering/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 | $0.01698 | $0.01698 |
| Opus 5 | $0.00849 | $0.00849 |
| Sonnet 5 | $0.00340 | $0.00340 |
| Haiku 4.5 | $0.00170 | $0.00170 |
Grade A, and why
laws-of-software-engineering 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 10d 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 — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Laws of Software Engineering
56 recurring laws, principles, and rules of thumb across software engineering. Cite one only when it sharpens the current decision; skip it if it's just a name-drop.
Source: paraphrased from lawsofsoftwareengineering.com.
Teams
- Conway's Law — Systems mirror the communication structure of the org that builds them. Apply: org design, re-orgs, platform rewrites.
- Brooks's Law — Adding people to a late project makes it later. Apply: hiring/resourcing decisions on slipping projects.
- Dunbar's Number — Informal structure breaks past ~150 stable relationships. Apply: org-size planning, team-of-teams design.
- Ringelmann Effect — Per-person productivity drops as groups grow. Apply: deciding team size, splitting a growing team.
- Price's Law — ~50% of output comes from ~√n contributors. Apply: key-person risk, retention prioritization.
- Putt's Law — Tech is often managed by those who don't understand it. Apply: escalation strategy, technical leadership gaps.
- Peter Principle — People get promoted until they stop being good at the job. Apply: promotion criteria, IC tracks.
- Bus Factor — Min # of people whose loss would halt the project. Apply: knowledge-sharing, documentation priority, on-call rotation.
- Dilbert Principle — Weak performers sometimes get promoted to limit their damage. Apply: reviewing promotion decisions critically.
Planning
- Premature Optimization (Knuth) — Optimize after measuring, not before. Apply: code review, performance work.
- Parkinson's Law — Work expands to fill the time given. Apply: deadline setting, sprint scoping.
- Ninety-Ninety Rule — First 90% takes 90% of the schedule; last 10% takes the other 90%. Apply: estimation sanity-check.
- Hofstadter's Law — It always takes longer than you expect, even accounting for this law. Apply: padding estimates.
- Goodhart's Law — When a measure becomes a target, it stops being a good measure. Apply: KPI design, incentive structures.
- Gilb's Law — Anything worth quantifying can be measured imperfectly better than not at all. Apply: pushing back on "we can't measure that."
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.
- 10d ago First seen · 80 lines · 1,698 tokens per session scan A 6634042d46db
laws-of-software-engineering CLAUDE.md is an instructions file published in the GitHub repository Y0lan/laws-of-software-engineering (10 stars, last pushed 4mo ago), licensed MIT. It adds 1,698 tokens to every session, about $0.0085 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.
Other instructions, from other repositories
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.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
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.