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.
npx agentmods add rules/renvia-code/best-cursor-rules/03-tool-usagegit clone --depth 1 https://github.com/Renvia-code/best-cursor-rulesWhat 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 | $0.00905 | $0.00905 |
| Opus 5 | $0.00452 | $0.00452 |
| Sonnet 5 | $0.00181 | $0.00181 |
| Haiku 4.5 | $0.00090 | $0.00090 |
Grade A, and why
03-tool-usage 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 yesterday.
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 — 167 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Tool Usage for This Repository
Tool Selection Strategy
codebase_search (Semantic Search)
When to use:
- Finding rules by topic or concept
- Understanding how similar rules are structured
- Discovering patterns across multiple rules
Examples:
✅ "How do other rules handle React patterns?"
✅ "What's the structure for backend rules?"
✅ "Find rules related to testing"
Don't use for:
❌ Finding specific file names (use glob_file_search)
❌ Exact text matches (use grep)
❌ Known file paths (use read_file)
grep (Exact Text Search)
When to use:
- Finding specific patterns in rules
- Locating frontmatter fields
- Finding all rules with certain globs
Examples:
✅ grep("alwaysApply: true") # Find always-on rules
✅ grep("globs:.*\\.tsx") # Find TypeScript rules
✅ grep("## Common Mistakes") # Find rules with this section
glob_file_search (Find Files)
When to use:
- Listing all rules in a category
- Finding rules by name pattern
- Getting file counts
Examples:
✅ glob_file_search("rules/frameworks/*.mdc")
✅ glob_file_search("**/*react*.mdc")
✅ glob_file_search("rules/**/*.mdc")
read_file (Direct Access)
When to use:
- Reading a specific rule file
- Checking rule format/structure
- Reviewing before editing
Examples:
✅ read_file("rules/frameworks/nextjs-15.mdc")
✅ read_file(".cursor/rules/01-rule-format.mdc")
Parallel Operations
✅ DO: Read multiple rules at once
// When comparing or reviewing multiple rules
read_file('rules/frameworks/nextjs-15.mdc')
read_file('rules/frameworks/react-19.mdc')
read_file('rules/backends/supabase.mdc')
// All execute in parallel
❌ DON'T: Read sequentially when independent
// Slow - waits between each
read_file('rules/frameworks/nextjs-15.mdc')
// wait...
read_file('rules/frameworks/react-19.mdc')
// wait...
Common Tasks
Adding a new rule
1. glob_file_search("rules/{category}/*.mdc") # See existing
2. read_file(".cursor/rules/01-rule-format.mdc") # Check format
3. read_file("rules/{category}/similar-rule.mdc") # Reference
4. write("rules/{category}/new-rule.mdc", content)
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.
- yesterday First seen · 167 lines · 905 tokens per session scan A ab815338f47a
03-tool-usage is a cursor rule published in the GitHub repository Renvia-code/best-cursor-rules (12 stars, last pushed 9mo ago), licensed CC0-1.0. It adds 905 tokens to every session, about $0.0045 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.
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