Stop Wasting Tokens: Pick the Right Model in Claude Code

Not every task needs the frontier model. A frontier model is the most advanced, capable model available at any given time — right now, that's Opus 4.6. It's tempting to use it for everything: if you have access to the best, why settle for less?. But doing so wastes tokens, wait time, and resources. Most daily development tasks don't require deep reasoning.

Claude Code already applies this logic internally. Its Explore agent runs on Haiku for fast codebase searches. The opusplan alias automates the full strategy: Opus reasons through planning, Sonnet handles execution.

TL;DR Use opusplan to plan with Opus and execute with Sonnet. Switch to Haiku for quick exploration. Don't use the frontier model for everything — allocate power where it actually matters.

Result:

> /model

    default
  ● opusplan   ← Plan: Opus 4.6 · Execution: Sonnet 4.6
    opus
    sonnet
    haiku

The strategy: plan, execute, explore

1. Plan with the frontier model

Deep reasoning is only justified when designing architecture, evaluating trade-offs, or making decisions that affect the entire project. This is where Opus makes the difference.

claude --model opus
# Or switch mid-session:
/model opus

2. Execute with Sonnet

Writing functions, tests, refactoring — doesn't need the same level of reasoning. Sonnet 4.6 delivers comparable intelligence at lower cost and higher speed.

/model sonnet

3. Explore with Haiku

Codebase searches, file reads, structure analysis. Read-only tasks where speed matters more than depth.

/model haiku

4. The shortcut: `opusplan`

If you don't want to switch manually, opusplan automates the strategy:

claude --model opusplan
# Or during a session:
/model opusplan

Opus activates during plan mode. When Claude transitions to execution, it switches to Sonnet automatically. This is exactly what Claude Code's native agents do — each task gets the right model for the job.

Reference

Model	Alias	Relative cost	Best for
Opus 4.6	`opus`	$$$	Architecture, complex debugging, design decisions
Sonnet 4.6	`sonnet`	$$	Daily development, implementation, tests
Haiku 4.5	`haiku`	$	Exploration, searches, simple tasks
Opus → Sonnet	`opusplan`	Mixed	Full workflow: plan + execute

Permanent configuration

Add the model to your settings.json so you don't have to choose every session:

{
  "model": "opusplan"
}

Or via environment variable:

export ANTHROPIC_MODEL=opusplan

If you want to further fine-tune Opus's reasoning during the planning phase, combine this strategy with Claude Code effort level adjustment: lower the effort for quick decisions and reserve high for architectural ones.

Official docs: Model configuration