Current as of March 2026. Opus 4.1 is the previous generation’s top-tier model, now largely superseded by Opus 4.5 and 4.6. The pricing hasn’t aged well — $15/$75 input/output for a 32K max output is a tough sell when newer Opus models exist at the same input price with better context limits. That said, if Opus 4.1 is already in your stack and working, there’s no urgent reason to migrate mid-project.
Specs
| Provider | Anthropic |
| Input cost | $15 / M tokens |
| Output cost | $75 / M tokens |
| Context window | 200K tokens |
| Max output | 32K tokens |
| Parameters | N/A |
| Features | function_calling, vision, reasoning |
What it’s good at
Tool Calling Reliability
It handles complex function schemas cleanly — fewer hallucinated arguments, fewer broken loops. For OpenClaw agents calling external APIs or local scripts, this is what you’re paying for.
Output Quality on Hard Problems
When reasoning is the bottleneck, this model doesn’t flinch. It follows negative constraints and multi-step instructions more reliably than Sonnet. The 32K output ceiling is the main limitation, not the quality.
Where it falls short
Extreme Cost
$75/M output tokens. That’s not a typo. At that price, even moderate output volumes get expensive fast. Opus 4.5 and 4.6 have made this model hard to justify for anything new.
Inference Speed
Slow. Not “slightly slower than Sonnet” slow — noticeably, painfully slow for anything interactive. Background tasks only.
Best use cases with OpenClaw
- Complex Refactoring — It understands dependencies across the full 200K window. Large-scale architectural changes where getting it wrong is expensive are where this model still earns its place.
- Strategic Planning — Synthesizing information from multiple documents into a coherent execution plan. Tedious for humans, well-suited for this model’s reasoning style.
Not ideal for
- Basic Data Extraction — Haiku handles simple JSON extraction at a fraction of the cost. There’s no reasoning advantage here for structured tasks.
- Real-time Chatbots — The latency is a dealbreaker. Don’t put this on anything with a user waiting on the other end.
Run it through Haimaker
Skip juggling API keys. One Haimaker key gives you access to every model on the platform. Tell OpenClaw:
Add Haimaker as a custom provider to my OpenClaw config. Use these details:
- Provider name: haimaker
- Base URL: https://api.haimaker.ai/v1
- API key: [PASTE YOUR HAIMAKER API KEY HERE]
- API type: openai-completions
Add the auto-router model:
- haimaker/auto (reasoning: false, context: 128000, max tokens: 32000)
Create an alias "auto" for easy switching. Apply the config when done.
Or skip model selection entirely — Haimaker’s auto-router picks the best model for each task so you don’t have to.
OpenClaw setup
Set your API key and OpenClaw routes automatically.
export ANTHROPIC_API_KEY="your-key-here"
That’s it. OpenClaw picks up Anthropic models automatically.
How it compares
- vs GPT-4o — GPT-4o is faster and much cheaper. Opus 4.1 wins on complex system prompt adherence, but it’s a narrow advantage for a significant cost premium.
- vs Claude 3.5 Sonnet — Sonnet handles 90% of developer tasks just fine. Opus 4.1 only makes sense if you’re hitting a consistent reasoning ceiling on Sonnet for specific hard tasks.
Bottom line
Expensive, slow, and now outclassed within Anthropic’s own lineup. Worth considering only if you’re maintaining an existing integration or have a specific task where Sonnet repeatedly fails and you need the reasoning depth. For anything new, look at Opus 4.5 or 4.6 first.
TRY CLAUDE OPUS 4.1 ON HAIMAKER
For setup instructions, see our API key guide. For all available models, see the complete models guide.