Overview
Claude Opus 4.5 is Anthropic's top-tier model, built for complex reasoning and long-horizon agentic coding. It sits at the head of the Claude ladder — Haiku → Sonnet → Opus — and is the model teams reach for when correctness and patience matter more than cost. Opus posts the strongest SWE-bench and agentic scores in the Claude line and is a favourite inside Claude Code for autonomous, multi-step engineering work.
Reviewers running large eval suites consistently rank Opus first among Claude models on pure reasoning and skill adherence, with high native behaviour rates that improve further when paired with structured "skills." The trade-off is price and latency: Opus is the most expensive Claude tier, so most workflows route everyday turns to Sonnet and escalate to Opus only for the hardest steps.
Key capabilities
- Top SWE-bench Verified scores in the Claude family
- Excellent long-horizon, autonomous agent behaviour
- Strong adherence to instructions and skills
- Deep, careful reasoning on ambiguous problems
At a glance
SWE-bench Verified
Class-leading (Claude)
Context
200K tokens
Tier
Opus (flagship)
Pricing: Premium Opus pricing — highest of the Claude tiers.
Pros & cons
What we like
- Best Claude model for hard reasoning and coding
- Reliable in long autonomous agent loops
- Excellent instruction and skill adherence
Trade-offs
- Most expensive Claude tier
- Higher latency than Sonnet/Haiku
- Overkill for routine chat
The verdict
Claude Opus 4.5 is the model to escalate to when a task is genuinely hard — autonomous agents, large refactors, high-stakes analysis. It wins on pure reasoning within the Claude line; pair it with Sonnet for cost control and reserve Opus for the steps that actually need it.
Best for: Autonomous coding agents and high-stakes reasoning.
Frequently asked questions
When should I use Opus instead of Sonnet?
Use Opus for the hardest reasoning, long autonomous agent runs and large code changes. Sonnet is the better default for everyday chat and cost-per-quality.
Is Claude Opus 4.5 good for coding?
Yes — it posts the strongest SWE-bench scores in the Claude family and is widely used inside Claude Code for multi-step engineering tasks.