Borrowing it
Nothing to install: this file belongs to vchelaru/XnaFiddle. 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/vchelaru/XnaFiddle/main/CLAUDE.mdgit clone --depth 1 https://github.com/vchelaru/XnaFiddleWrote 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/vchelaru/xnafiddle/claude-md)<a href="https://agentmods.dev/instructions/vchelaru/xnafiddle/claude-md"><img src="https://agentmods.dev/badge/instructions/vchelaru/xnafiddle/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 | $0.00586 | $0.00586 |
| Opus 5 | $0.00293 | $0.00293 |
| Sonnet 5 | $0.00117 | $0.00117 |
| Haiku 4.5 | $0.00059 | $0.00059 |
Grade A, and why
XnaFiddle 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 2d 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 — 30 lines — stays where its author put it; the contents beside it link to each section on GitHub.
XnaFiddle Repository Guidelines
What Is This?
XnaFiddle is a standalone KNI game runner with an in-browser C# editor. It is a Blazor WASM app with a WebGL canvas and Monaco code editor that lets users write, compile, and run XNA/KNI game code directly in the browser.
Skills
On any task — research, maintenance, new features, bug fixes, refactors, docs, reviews — first check whether an available skill applies, and load it before proceeding. Skills (e.g. file-loading, intellisense, verify, run, code-review) carry condensed, repo-specific knowledge that prevents rediscovering subsystem details from scratch. When a skill matches the work, invoke it; if none fit, say so briefly and continue. This check is in addition to, not a replacement for, the Agent Workflow below.
Finding an existing skill stale or wrong → fix it directly, no suggestion or confirmation needed. This is correcting an inaccuracy, not a new-content judgment call.
Proactively suggest a new skill when — and only when — you finish work having re-derived reusable subsystem knowledge that no skill covers. Don't wait to be asked; surface it as a suggestion and let the user decide (don't create one unprompted). But the bar is high: every skill line costs tokens on every relevant load, so err toward not proposing. Only suggest when you're confident the knowledge will be re-hit by a concrete upcoming task, not for one-off facts the code already records or that this conversation alone needed. When unsure, stay silent.
Agent Workflow
For every task, invoke the appropriate agent from .claude/agents/ before proceeding. The agent's instructions provide guidelines for how the task should be performed. Before doing any work, announce which agent you are using such as "Invoking coder agent for this task..."
Available agents:
- coder — Writing or modifying code and unit tests for new features or bugs
- qa — Testing, reviewing changes, and verifying correctness
- refactoring-specialist — Refactoring and improving code structure
- docs-writer — Writing or updating documentation
- product-manager — Breaking down tasks and tracking progress
- security-auditor — Security reviews and vulnerability assessments
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.
- 2d ago First seen · 30 lines · 586 tokens per session scan A 818f6bf5d7b2
XnaFiddle CLAUDE.md is an instructions file published in the GitHub repository vchelaru/XnaFiddle (13 stars, last pushed yesterday), licensed MIT. It adds 586 tokens to every session, about $0.0029 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 2026-09-04.
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