Deepseek v4 Pro feels like Claude Opus 4.6 in it's personality but here's what I did find out about costs:

I did cut loose Deepseek v4 on a decent sized Typescript codebase and asked it to only focus on a single endpoint and go in depth on it layer by layer (API, DTOs, service, database models) and form a complete picture of types involved and introduced and ensure no adhoc types are being introduced.

It developed a very brief but very to the point summary of types being introduced and which of them were refunded etc.

Then I asked it to simplify it all.

It obviously went through lots of files in both prompts but total cost? Just $0.09 for the Pro version.

On Claude Opus I think (from past experience before price hikes) these two prompts alone would have burned somewhere between $9 to $13 easily with not much benefit.

Note - I didn't use Open router rather used the Deepseek API directly because Open router itself was being rate limited by Deep seek.

I find a lot of the inefficiency also comes from the model just randomly poking around and grepping all the time which is the fault of the harness. I ended up building a Prolog based MCP where I use tree-sitter to parse the code into a graph, and then the model can just ask questions like 'what are all the functions connected to this function'. So, in case you're trying to focus on what a particular endpoint is doing, you can trivially and predictably trace the whole subgraphs of calls.

https://github.com/yogthos/chiasmus

Even taking into account the fact that they are billing at 75% discount it's still quite cheaper

How did you use it? OpenRouter, or provider directly?

Only similarity it has to Opus 4.6 is the 4 in the name. I do not understand these dishonest comparisons. OOS models are vool, cheap and promising for a future -- but why are we pretending they are better than they are?