AI Hack: Which Claude Code effort level to use

Running Claude Code on max effort for every task?

You're paying for verification you don't need, and waiting longer for it.

Anthropic engineer Thariq Shihipar tested effort levels on real builds and on Terminal-Bench 3.0. His rule of thumb:

Low → quick, in-the-loop work: brainstorming, sketches, easy changes Medium → most everyday engineering, like new features High → when edge cases and verification matter, like fixing a bug in an older codebase Max → when Claude should work fully on its own: end-to-end builds, hunting security bugs

What higher effort actually buys you: more testing, more edge cases, more decisions made on its own.

What it doesn't buy you: higher effort reduced failures from missed edge cases. It did not fix failures where Claude took the wrong approach.

His loop for new features:

1. Give Claude a spec and let it interview you for the gaps

2. Build on low/medium effort

3. Review, and iterate on low/medium

4. Verify and test on high

Switch anytime with /effort, even mid-conversation. On the newest models, changing effort doesn't break the prompt cache.

The 3 prompts for his loop:

Interview (low effort): "Here's my spec. Before writing any code, interview me about anything missing or ambiguous, one question at a time. When we're done, write the final spec to SPEC.md."

Build (low effort): "Implement SPEC.md. Keep it simple. Don't add anything the spec doesn't ask for."

Verify (high effort): "Review the implementation against SPEC.md like a strict reviewer. List the edge cases, write tests for them, run them, and report every failure before fixing anything.

You can use medium effort using Opus 5.5 for Interview and Build , and verify using high effort.

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AI Hack: Which Claude Code effort level to use