What Changed — A Hybrid Model Strategy
A new workflow has emerged for Claude Code users: the /opusplan mode. This isn't a built-in CLI flag (yet), but a powerful prompt pattern you can use today. The strategy is simple: you instruct Claude Code to first use Claude Opus 4.6—Anthropic's most capable reasoning model—to analyze your complex task, break it down, and create a detailed, step-by-step implementation plan. Then, you have it switch to Claude Sonnet 4.6 to execute that plan, writing the actual code.
This leverages the key strength of each model. Opus excels at high-level reasoning, understanding nuanced requirements, and architecting robust solutions. Sonnet is faster, more cost-effective, and perfectly capable of following clear instructions to produce quality code.
Why It Works — Optimal Model Economics
Using Opus for an entire coding session can be expensive and sometimes slower than necessary for straightforward implementation. The /opusplan pattern applies a classic "think then do" agentic workflow manually. You get Opus's superior planning intelligence to ensure the architecture and approach are sound, then you benefit from Sonnet's speed and lower cost for the bulk of the token usage.
This is especially valuable for:
- Large refactors: Where the plan is everything.
- New feature architecture: Designing the module structure and interfaces.
- Complex bug diagnosis: Reasoning through the root cause before writing the fix.
How To Apply It — The Prompt Pattern
You implement this by structuring your initial prompt to Claude Code with clear phase instructions. Here's the template:
claude code "[Your task here]"
IMPORTANT: Use this two-phase approach.
PHASE 1 (Use Opus 4.6):
1. Analyze the full task and requirements.
2. Create a comprehensive, step-by-step implementation plan.
3. List all files to be created or modified.
4. Outline the key logic for each step.
PHASE 2 (Switch to Sonnet 4.6):
Now, execute the plan from Phase 1. Write all the code, create the files, and implement the solution. Do not re-analyze the high-level approach; follow the plan.
For example, to build a new API endpoint:
claude code "Add a POST /api/users/webhook endpoint to our Express app that validates a signature header, parses the JSON body, and logs events to our audit table."
IMPORTANT: Use this two-phase approach...
[Paste the template from above]
Claude Code will process this, using its Opus context to build the plan, then effectively "hand off" to its Sonnet-level execution for the coding. The result is a well-thought-out solution built efficiently.
Pro Tip: Integrate into Your CLAUDE.md
Make this your default for larger tasks by adding a section to your project's CLAUDE.md file:
## Model Strategy for Complex Tasks
For tasks involving new architecture, major refactors, or complex logic:
1. First, request a detailed implementation plan from Opus.
2. Then, execute that plan using Sonnet.
Use the prompt: "Please proceed with the Opus-plan-then-Sonnet-execute strategy for this task."
This tells Claude Code to apply the hybrid model strategy automatically when it sees that prompt, saving you from typing the full instructions each time.
