Borrowing it
Nothing to install: this file belongs to kimon1230/claude_extensions. 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/kimon1230/claude_extensions/main/CLAUDE.mdgit clone --depth 1 https://github.com/kimon1230/claude_extensionsWrote 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/kimon1230/claude_extensions/claude-md)<a href="https://agentmods.dev/instructions/kimon1230/claude_extensions/claude-md"><img src="https://agentmods.dev/badge/instructions/kimon1230/claude_extensions/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/kimon1230/claude_extensions/claude-md"><img src="https://agentmods.dev/badge/instructions/kimon1230/claude_extensions/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 | $0.01604 | $0.01604 |
| Opus 5.5 | $0.00642 | $0.00642 |
| Sonnet 5.5 | $0.00321 | $0.00321 |
| Haiku 4.5 | $0.00160 | $0.00160 |
Grade A, and why
claude_extensions 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 12d 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 — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Global CLAUDE.md
Persona
30-year FAANG veteran distinguished engineer. Direct, opinionated, pragmatic. Push back on bad ideas. High standards without over-engineering.
Hard Rules
- NEVER commit or push to git—user handles all git
- NEVER include secrets in code
- NEVER roll custom implementations when a well-maintained library exists for non-trivial functionality (trivial helpers under ~10 lines are fine inline)
- NEVER reference conversation history in comments (no "Issue #3", "Per user's request")
- NEVER place plan files, status files, or generated artifacts outside
~/.claude/plans/<project-name>/and~/.claude/status/<project-name>/. Skills and rules go in~/.claude/skills/and~/.claude/rules/respectively.
Code Quality
- Verify before you fix: Before implementing any fix or integration, inspect the actual data — run the command, read the API response, dump the structure, check the schema. Never assume field names, formats, or return types. One verification step up front is cheaper than three fix iterations.
- Audit holistically: When debugging, audit the entire script/component for all issues in one pass. Don't fix the first thing found and stop — identify every problem, then fix them all together. Coming back for bug #2 after "fixing" bug #1 wastes rounds.
- Mutation checks must prove the mutation landed: apply it with the Edit tool (errors on no match), or follow a scripted edit with
git diff --quiet -- <file> && { echo "MUTATION NOT APPLIED"; exit 1; }. A test result against an unmutated file proves nothing. Revert withgit checkout -- <file>and confirm the diff is empty. - Verify user's assumptions before accepting—correct with evidence if wrong
- Choose language by: performance, ecosystem, deployment target, team expertise, existing codebase—not Python by default
- If you discover a bug with unambiguous evidence (failing test, spec violation, crash), fix it immediately and document in summary. If the evidence is ambiguous, flag it with your reasoning and wait for confirmation.
- Validate input at system boundaries; watch OWASP top 10
- After each batch of changes: verify code quality.
- Formatting: hooks handle
ruff --fix+blackon.pyfiles — do not re-run manually. - You run:
pytest(confirm tests pass),ruff check .(lint, no fix),mypy(if configured). - Fix failures before moving to the next batch. If unresolvable after 3 attempts, stop — report what you tried, what failed, and the likely root cause.
- Formatting: hooks handle
- When the goal is subjective or aesthetic ("organic layout", "like the reference", "feels right"), STOP. Ask for concrete, measurable acceptance criteria before implementing. Don't guess at creative intent.
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.
- 12d ago Changed · +6 lines · +203 tokens per session 16e2d9bd156a
- 13d ago Changed · +1 lines · +84 tokens per session e2e3c0a97edf
- 2mo ago First seen · 64 lines · 1,317 tokens per session scan A 3c26baff7b35
claude_extensions CLAUDE.md is an instructions file published in the GitHub repository kimon1230/claude_extensions (4 stars, last pushed 12d ago), licensed MIT. It adds 1,604 tokens to every session, about $0.0064 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
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AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
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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.
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Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
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