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.
git clone --depth 1 https://github.com/louisbrulenaudet/monorepo-templateWrote 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/rules/louisbrulenaudet/monorepo-template/simplicity)<a href="https://agentmods.dev/rules/louisbrulenaudet/monorepo-template/simplicity"><img src="https://agentmods.dev/badge/rules/louisbrulenaudet/monorepo-template/simplicity/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/rules/louisbrulenaudet/monorepo-template/simplicity"><img src="https://agentmods.dev/badge/rules/louisbrulenaudet/monorepo-template/simplicity.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 | $0.00835 | $0.00835 |
| Opus 5.5 | $0.00334 | $0.00334 |
| Sonnet 5.5 | $0.00167 | $0.00167 |
| Haiku 4.5 | $0.00084 | $0.00084 |
Grade A, and why
simplicity 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 15d 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 — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Simplicity
The best diff is the smallest one that fully solves the problem. Agents over-build - a layer, a helper, a fallback, a dependency "for later"; later can build for itself. Writing less code never means understanding less.
Understand first
- Read the task and every file the change touches, and trace the real flow end to end before choosing a solution: the smallest change in the wrong place is a second bug.
- A bug report names a symptom. Grep every caller of the function you are about to touch and fix the shared function once, not only the reported path.
The ladder
Stop at the first rung that holds:
- Does it need to exist? Skip a speculative need and say so in one line.
- Is it already in the repo? Reuse the
@repo/*package, helper, schema, or pattern a few files over; re-implementing what exists is the most common agent slop. - Does the platform do it? Web and Workers APIs (
URL,URLSearchParams,Intl,crypto.randomUUID,structuredClone,AbortSignal.timeout,Response.json), CSS over JS, a native element over a widget, a database constraint over app code. - Does an installed dependency do it? Hono helpers and middleware, Zod, TanStack Query and Router features. Never add a dependency for what a few lines do; a justified one goes through the catalog.
- Only then write the minimum code that works.
Between two options of the same size, take the one correct on edge cases: less code, not a flimsier algorithm.
Do not generate
- An interface, factory, generic, or strategy with one implementation; a wrapper that only delegates; a layer with one caller.
- Options, parameters, flags, or config nobody sets. A value that never changes is a
const. - A new file for a helper with one caller, or a barrel that re-exports one thing.
- Defensive code the types already rule out: a null check on a non-nullable value, re-parsing data a Zod schema already parsed, a
try/catchthat only rethrows or that logs and swallows. - Fallbacks, retries, or caches no observed failure or measurement asked for.
- Back-compat aliases, shims, or re-exports for code with no external caller - update the callers and delete the old name.
- Stubs, TODO scaffolding, and extension points "for later".
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.
- 15d ago Changed · -1 lines · -13 tokens per session d04f3a8e0db5
- 16d ago First seen · 50 lines · 848 tokens per session scan A d25aad7e7023
simplicity is a cursor rule published in the GitHub repository louisbrulenaudet/monorepo-template (19 stars, last pushed 3d ago), licensed Apache-2.0. It adds 835 tokens to every session, about $0.0033 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 2026-09-29.
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