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/MCKRUZ/claude-code-masteryWrote 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/mckruz/claude-code-mastery/performance)<a href="https://agentmods.dev/rules/mckruz/claude-code-mastery/performance"><img src="https://agentmods.dev/badge/rules/mckruz/claude-code-mastery/performance/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/mckruz/claude-code-mastery/performance"><img src="https://agentmods.dev/badge/rules/mckruz/claude-code-mastery/performance.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 | $0.00169 | $0.00169 |
| Opus 5.5 | $0.00068 | $0.00068 |
| Sonnet 5.5 | $0.00034 | $0.00034 |
| Haiku 4.5 | $0.00017 | $0.00017 |
Grade A, and why
performance 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 1mo 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
Performance
Context Window
- Avoid last 20% for large refactoring or multi-file features. Single-file edits and docs are fine near the limit.
- When context is getting long, finish current work cleanly rather than starting new complex tasks.
Research Time Limits
- If a single site or source takes more than 5 minutes to fetch or return useful results, abandon that source and move on.
- One or two attempts per source max, then pivot to the next.
Build Troubleshooting
- Build fails → analyze the actual error message first, don't guess.
- Fix incrementally — one error at a time, verify between fixes.
- Don't suppress warnings to make a build pass. Fix the underlying issue.
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.
- 1mo ago First seen · 20 lines · 169 tokens per session scan A fe33ea166599
performance is a cursor rule published in the GitHub repository MCKRUZ/claude-code-mastery (11 stars, last pushed 5mo ago), licensed MIT. It adds 169 tokens to every session, about $0.0007 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 2026-08-30.
Other cursor rules, from other repositories
llm-layer
LLM provider implementation patterns.
skill-rails-api
Padrões DARE para APIs em Ruby on Rails 8 — API mode, ActiveRecord, Solid Queue, Solid Cable, Action Cable, strong parameters, services, serializers (Blueprinter/Alba), Devise/JWT, rack-attack, rswag/grape-swagger.
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.
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.