A Test of Anthropic’s Best Coding Model

Anthropic has been buzzing as of late. It recently caused a stock market meltdown with its release of the Claude Cowork tool that tanked the stocks of major SaaS providers across the world. And now they’re about to revolutionize reasoning models with their latest release, Claude Opus 4.6, which they’re claiming as their best coding model yet. 

Whether it is up to the claims or not we’ll find out in this article where we put it to the test to see how well it fares across coding and reasoning tasks. 

Claude Opus 4.6!

The Opus line is the top tier of Anthropic’s Claude family, built for heavy reasoning and advanced coding. These models are designed to handle long, multi-step tasks that need planning, context retention, and structured problem solving.

Claude Opus 4.6 is the newest entry in this lineup and Anthropic’s most capable coding model to date. It focuses on making reasoning sharper, code generation cleaner, and long workflows easier to manage.

What Opus 4.6 brings to the table:

• Stronger multi-step reasoning: Better planning and handling of edge cases in complex problems.
• Improved coding performance: More reliable code generation, debugging, and consistency across large codebases.
• Longer context handling: Sustains context across extended tasks and large documents. Token window of up to 1 million tokens (128k output tokens). 
• Workflow awareness: Designed for multi-stage projects like software development and analytical work. This is extended across multi-file projects, where an entire project can be imported to work upon.
• Adaptive thinking: Opus 4.6 can think with different effort levels. You can tell Opus how hard to think: low, medium, high, or max, and it decides when to spend more compute on tough problems.

How to access Claude Opus 4.6?

Claude Opus 4.6 is a premium, paid model aimed at users who need top-tier performance for coding and complex workflows. It’s available both inside Claude and through the Anthropic developer platform.

• Claude app access: Available to Pro, Max, Team, and Enterprise subscribers on Claude.

• Developer access: Available through the Claude Developer Platform via the Anthropic API for usage-based billing.

• Cloud Platforms: Offered through major cloud providers like Cursor, Windsurf that integrate Anthropic models for enterprise and developer use.

The pricing is the same as it was for Claude Opus 4.5. But here’s the catch! The tokens consumed is almost 5 times more than it was on its Opus 4.5. So even though the cost is the same, upon usage Claude Opus 4.6 API will be more expensive. 

Putting it to Test

All the good word for Opus would be of no avail, if its performance falls flat in real-world use cases. To put it to test, I’d be evaluating how well it responds to 4 types of queries. The queries are designed to test:

1. Multi-step planning and agent-style workflows
2. Large-scale code refactoring and feature engineering
3. Algorithmic reasoning under real-world constraints
4. System-level debugging and fault diagnosis

Multi-step agent workflow

This test measures planning ability and long-horizon reasoning.

Build a small SaaS analytics dashboard. Take the following things into consideration.
Break this into phases:
• Requirements gathering
• System design
• Database schema
• Backend API design
• Frontend architecture
• Deployment plan
For each phase:
1. Produce concrete deliverables
2. Identify risks
3. Propose mitigation strategies
At the end, summarize the full execution roadmap.

Response:

Color me impressed! For the time it took to create one, this is a really high quality dashboard. It is reactive and has a responsive design. For concepts and prototypes, this functionality could prove useful.

Code refactor and feature expansion

This test checks whether Opus can understand messy legacy code, redesign it, and extend it with production-grade features. I’ve attached a messy code wit ha lot of faults to see how many of them could be rectified by the model.

Refactor this project into a clean, production-ready architecture and add the following features:
1. JWT-based authentication
2. Password hashing and validation
3. Structured logging
4. Persistent database storage (replace the current file system logic)
5. REST API interface
6. Unit tests for core functionality
Constraints:
• Follow clean architecture principles
• Eliminate global state
• Add proper error handling and input validation
• Document your architectural decisions
Use the attached code. 

This took too long. Long enough for it to prompt me with this:

But wait was completely worth it. The code was comprehensive, functional and satisfied each on of the criteria that I had established in the prompt. It provided a number of files each of which fulfilled a purpose. The code was modular, well documented and the architecture file outlined the project in an understandable manner.

Algorithmic reasoning under constraints

This test evaluates deep reasoning, tradeoff analysis, and implementation quality.

Design and implement an efficient system to detect duplicate files across millions of records.
Requirements:
• Files may be partially corrupted
• Memory is limited to 2GB
• The system must scale horizontally
• Provide time and space complexity analysis
• Include a working Python prototype
• Explain your design step by step and justify tradeoffs.
Explain your design step by step and justify tradeoffs. 

Response:

Opus provided an article in the time it would take one to open a text processor. The design prototype was sound and stages clearly covering individual components. The justifications for different components in the system were acceptable.

Windows system debugging

This test examines structured troubleshooting and real-world diagnostic reasoning.

My Windows PC has been experiencing intermittent freezes and crashes for about a month.
Symptoms:
• Random system freezes during normal use
• Occasional Blue Screen of Death (BSOD)
• Chrome tabs frequently crash with memory errors
• The system suddenly stopped booting entirely
• After removing one RAM stick, the PC boots again
• With the remaining RAM stick installed, instability still occurs
I suspect a hardware or memory-related issue.
Provide a structured troubleshooting plan that includes:
1. Likely root causes ranked by probability
2. Step-by-step diagnostic tests to isolate the issue
3. Recommended Windows tools and third-party utilities
4. Hardware checks and stress tests
5. A clear decision tree for repair or replacement
Explain your reasoning at each stage. 

Response:

Amazing! This is one of the problems I have been facing for the past few weeks and couldn’t seem to fix regardless of what I tried. Perusing through Reddit forums and LTT threads didn’t help by much. The response provided by Claude Opus was quite helpful. It not only summarised almost everything that I had been through for the past few weeks, but also graded it based off the likelihood of it being the root cause of the problem. The answer was grounded in truth and the commands that followed were actually helpful.

For the Nerds!

If interested in performance across AI benchmarks the following would assist:

High numbers across most reasoning and genetic benchmarks against other state of the art models. There is not only a clear advantage over its predecessor, but a huge difference in capabilities compared to its contemporaries. Further cementing its position in the coding and reasoning throne.

If you’re interested in more benchmarks or are curious about its performance on a specific benchmark, read the official evaluations page of the model.

Conclusion

Was it worth the hype? In terms of coding and reasoning Claude demonstrated once again, that it has a clear lead. Opus 4.6 just helped extend that lead further. With sandbox style code execution, ability to work on entire projects at once and adaptive thinking capacities to optimize token consumption based off the workload, Claude is offering more than a Good Coder!

The entire Claude ecosystem has been optimised to accomodate for this new entrant, and the latest model is able to make the most out of these added functionalities.

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