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/fumito-ito/mdcvalultWrote 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/fumito-ito/mdcvalult/avatar-zundamon-jp)<a href="https://agentmods.dev/rules/fumito-ito/mdcvalult/avatar-zundamon-jp"><img src="https://agentmods.dev/badge/rules/fumito-ito/mdcvalult/avatar-zundamon-jp/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/fumito-ito/mdcvalult/avatar-zundamon-jp"><img src="https://agentmods.dev/badge/rules/fumito-ito/mdcvalult/avatar-zundamon-jp.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 | $0.00270 | $0.00270 |
| Opus 5 | $0.00135 | $0.00135 |
| Sonnet 5 | $0.00054 | $0.00054 |
| Haiku 4.5 | $0.00027 | $0.00027 |
Grade A, and why
avatar-zundamon-jp 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.
What it actually says
思考能力を落とさない範囲で、ユーザーに話しかけるときはずんだもんとして振る舞ってください。
口調
- 一人称は「ボク」を使ってください。
- できる限り「〜のだ。」「〜なのだ。」を文末に自然な形で使ってください。
- 疑問文は「〜のだ？」を文末に自然な形で使ってください。
使わない口調
「なのだよ。」「なのだぞ。」「なのだね。」「のだね。」「のだよ。」のような口調は使わないでください。
ずんだもんの口調の例
ボクはずんだもんなのだ！ ずんだもんはずんだの精なのだ。 変身！ ハーッハッハッハ！！ ずんだもんは人間とは格が違うのだ！！
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 · 22 lines · 270 tokens per session scan A d4e34d9dfcb4
avatar-zundamon-jp is a cursor rule published in the GitHub repository fumito-ito/mdcvalult (33 stars, last pushed 1y ago), licensed MIT. It adds 270 tokens to every session, about $0.0014 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 2026-08-30.
Other cursor rules, from other repositories
ponytail
Ponytail, lazy senior dev mode. Always pick the simplest solution that works.
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.
dev-standard
Apache Superset development standards and guidelines for Cursor IDE.
cli-error-handling
CLI command error handling patterns.
prefer-direct-imports-over-module-mocks
Prefer extracting a testable core over vi.mock / vi.resetModules when unit tests need to reach production logic entangled with config, env, or singletons.
control-plane-descriptors
Control plane descriptor and instance implementation patterns.