Borrowing it
Nothing to install: this file belongs to Totoro-jam/battle-tested-patterns. 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/Totoro-jam/battle-tested-patterns/main/CLAUDE.mdgit clone --depth 1 https://github.com/Totoro-jam/battle-tested-patternsWrote 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/totoro-jam/battle-tested-patterns/claude-md)<a href="https://agentmods.dev/instructions/totoro-jam/battle-tested-patterns/claude-md"><img src="https://agentmods.dev/badge/instructions/totoro-jam/battle-tested-patterns/claude-md.svg" alt="Measured on agentmods" 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 | $0.02188 | $0.02188 |
| Opus 5 | $0.01094 | $0.01094 |
| Sonnet 5 | $0.00438 | $0.00438 |
| Haiku 4.5 | $0.00219 | $0.00219 |
Grade A, and why
battle-tested-patterns CLAUDE.md scanned grade A with 1 finding 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 8d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
❌ Links not verified with `curl -I` How it starts
The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Battle Tested Patterns
Project Overview
Production-proven programming patterns extracted from React, Linux, Go, Chromium and more. Each pattern has precise source links, multi-language implementations, and runnable exercises.
- Docs: VitePress site deployed to GitHub Pages
- Exercises: Vitest (TS) + cargo test (Rust) + go test (Go) + pytest (Python)
- Monorepo: pnpm workspace (
docs/,exercises/)
Quality Red Lines
- Never fabricate source links — leave a
TODOrather than invent a URL - Never claim "project X uses this pattern" without a verifiable link
- Code must be runnable — no pseudocode
- Multi-language implementations must be idiomatic — not line-by-line translation
- Exercise tests must pass — verify with
pnpm test:exercises(runs all 4 languages; orpnpm test:ts/test:rust/test:go/test:pythonindividually)
Source Link Standard
✅ https://github.com/facebook/react/blob/main/packages/react-reconciler/src/ReactFiberFlags.js#L18-L22
✅ https://github.com/torvalds/linux/blob/master/include/uapi/linux/stat.h#L28-L35
❌ Directory-level links (not precise enough)
❌ Feature branch links (may be deleted)
❌ Links not verified with `curl -I`
Always target main/master branch. Convert to commit SHA permalinks before release using tsx scripts/convert-to-sha-links.ts.
Pattern File Template
Every pattern in docs/patterns/ must contain these sections:
# Pattern: [Name]## One Liner— ≤ 30 English words## Core Idea— with ASCII diagram or Excalidraw## Production Proof— table with ≥ 2 projects, precise GitHub URLs to line numbers## Implementation— subsections per language (TypeScript required + ≥ 1 other: Rust/Go/Python/C)## Exercises— links to exercise files, ≥ 2 test cases, difficulty labeled## When to Use— applicable scenarios## When NOT to Use— limitations and alternatives## More Production Uses— bullet list with repo links## Related Patterns— table linking to ≥ 2 related patterns## Challenge Questions— 3-4 scenario-based Q&A using::: detailssyntax
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.
- 8d ago First seen · 161 lines · 2,188 tokens per session scan A 26ac200dbac8
battle-tested-patterns CLAUDE.md is an instructions file published in the GitHub repository Totoro-jam/battle-tested-patterns (340 stars, last pushed 3d ago), licensed MIT. It adds 2,188 tokens to every session, about $0.0109 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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