Claude Model Lineup in Copilot
Claude Haiku (e.g., 3.5 Haiku)
Best for: speed and high-volume, simple tasks
- Quick code completions and inline suggestions
- Simple refactors, renaming, boilerplate generation
- Fast Q&A about syntax or small snippets
- When latency matters more than deep reasoning
- Cost-efficient for routine work
Claude Sonnet (3.5 / 3.7 / 4 / 4.5)
Best for: the everyday “workhorse” — balanced speed and capability
- General-purpose coding, feature implementation, bug fixes
- Agent mode / multi-file edits across a codebase
- Writing tests, reviewing PRs, explaining moderately complex code
- Sonnet 3.7 introduced hybrid/extended reasoning (a “thinking” mode) — good for tasks needing a bit more step-by-step logic
- Sonnet 4 / 4.5 improved at longer agentic tasks, tool use, and staying on track over many steps
This tier is the default choice for most daily development.
Claude Opus (e.g., Opus 4 / 4.1 / 4.8)
Best for: the hardest problems requiring deep reasoning
- Complex architecture design and large-scale refactoring
- Debugging subtle, multi-system issues
- Long-horizon agentic tasks with many dependencies
- Deep code analysis across large codebases
- Situations where quality/correctness outweighs speed and cost
Opus is the most capable (and most “expensive” in premium-request terms), so it’s typically reserved for tasks where the extra reasoning pays off.
Quick Decision Guide
| Need | Model tier |
|---|---|
| Fast completions, simple edits, low cost | Haiku |
| Day-to-day coding, agent tasks, tests, reviews | Sonnet |
| Deep reasoning, complex architecture, tricky debugging | Opus |
Practical Notes for Copilot
- Premium requests: Higher-tier models (Opus especially) consume more of your premium request budget. Sonnet is usually the sweet spot for cost vs. capability.
- “Thinking” variants: Some models (Sonnet 3.7+, Opus 4+) offer extended reasoning — worth enabling for complex logic, but slower.
- Agent mode: Sonnet 4.x and Opus 4.x handle multi-step, tool-using agent workflows best.
- Availability depends on your Copilot plan (Free/Pro/Pro+/Business/Enterprise) and may require enabling models in settings.
Rule of thumb: Start with Sonnet. Drop to Haiku when you want speed and are doing something simple. Reach for Opus only when Sonnet struggles with a genuinely hard problem.
Note: Anthropic and GitHub update the available model list frequently, so check Copilot → model picker in VS Code for exactly which Claude versions your plan currently offers.