Chapter 06 · For programming contexts

Best practices.
Ruthless editing.

The single highest-leverage practice is ruthless editing. Anthropic's own best-practices page puts it plainly: "If Claude already does something correctly without the instruction, delete it."

Every line is pure token-waste and attention dilution.

🎯

Write specific rules with concrete examples

Good and bad patterns. Trigger.dev's engineering blog notes examples — especially counterexamples — outperform abstract prose.

⚠️

Avoid contradictions aggressively

GitHub Copilot's docs explicitly warn that conflicting rules across personal, repo, and org levels produce unpredictable behavior.

🧹

Don't mix legacy with modern

Cursor's docs warn the same about mixing legacy .cursorrules with modern .cursor/rules/ files.

Version-control your skills

Source code that affects your software.

Commit .cursor/rules/, .claude/skills/, and AGENTS.md to your repo and review them in PRs like any other code. But audit for secrets.

Do this

Treat skills as real code

Commit themVersion-control skills in the same repo as the code they shape.
Review them in PRsLike any change, they affect deterministic agent behavior.
Prune quarterlyDelete anything the model already does right; delete contradictions.
Use AGENTS.md as shared source of truthSupplement with tool-specific rules for tool-specific features.

Real risks

Audit before you trust

Secrets in skillsAudit them for secrets — they're committed to source control.
Stale rules cause confident bugsBecause rules are injected with high authority, the AI aggressively applies a rule six months out of date — forcing an old SDK syntax, a deprecated API, or a removed framework method. The symptom isn't a random mistake; it's the AI refusing to use the correct modern pattern.

Team collaboration

AGENTS.md wins as the shared source of truth.

Since it works across nearly every tool. Hub repos like Continue.dev's, cursor.directory, and the anthropics/skills repo all provide importable rule packages for common frameworks.

Continue.dev's Hub

cursor.directory

anthropics/skills

awesome-cursor-rules-mdc (~3.5k ★)