They are not blacklisted. You are allowed to use the API at commercial usage pricing. You are just not allowed to use your Claude Code subscription with OpenCode (or any other third‑party harness for the record).
If you're not paying full-fat API prices, then probably.
From what I've heard, the metrics used by Anthropic to detect unauthorized clients is pretty easy to sidestep if you look at the existing solutions out there. Better than getting your account banned.
Sometimes people want to be real pedants about licensing terms when it comes to OSS, assuming such terms are completely bulletproof, other times people don't think the terms of their agreement with a service provider should have any force at all.
The highest in in the industry for API pricing right now is GPT-5.4-Pro, OpenRouter adding that as an option in their Auto Router was when I had to go customise the routing settings because it was not even close to providing $30/m input tokens and $180/m output tokens of value (for context Opus 4.6 is $5/m input and $25/m output)
(Ok, technically o1-pro is even more expensive, but I'm assuming that's a "please move on" pricing)
With Anthropic, you either pay per token with an API key (expensive), or use their subscription, but only with the tools that they provide you - Claude, Claude Cowork and Claude Code (both GUI and CLI variants). Individuals generally get to use the subscriptions, companies, especially the ones building services on top of their models, are expected to pay per token. Same applies to various third party tools.
The belief is that the subscriptions are subsidized by them (or just heavily cut into profit margins) so for whatever reason they're trying to maintain control over the harness - maybe to gather more usage analytics and gain an edge over competitors and improve their models better to work with it, or perhaps to route certain requests to Haiku or Sonnet instead of using Opus for everything, to cut down on the compute.
Given the ample usage limits, I personally just use Claude Code now with their 100 USD per month subscription because it gives me the best value - kind of sucks that they won't support other harnesses though (especially custom GUIs for managing parallel tasks/projects). OpenCode never worked well for me on Windows though, also used Codex and Gemini CLI.
>or perhaps to route certain requests to Haiku or Sonnet instead of using Opus for everything, to cut down on the compute
You can point Claude Code at a local inference server (e.g. llama.cpp, vLLM) and see which model names it sends each request to. It's not hard to do a MITM against it either. Claude Code does send some requests to Haiku, but not the ones you're making with whatever model you have it set to - these are tool result processing requests, conversation summary / title generation requests, etc - low complexity background stuff.
Now, Anthropic could simply take requests to their Opus model and internally route them to Sonnet on the server side, but then it wouldn't really matter which harness was used or what the client requests anyway, as this would be happening server-side.
Sounds pretty sane, the same way how OpenWebUI and probably other software out there also has a concept of “tool models”, something you use for all the lower priority stuff.
Actually curious to hear what others think about why Anthropic is so set on disallowing 3rd party tools on subscriptions.
The sota models are largely undifferentiated from each other in performance right now. And it’s possible open weight models will get “good enough” relatively soonish. This creates a classic case where inference becomes a commodity. Commodities have very low margins. Training puts them in an economic hole where low margins will kill them.
So they have to move up the stack to higher margin business solutions. Which is why they offer subsidized subscription plans in the first place. It’s a marketing cost. But they want those marketing dollars to drive up the stack not commodity inference use cases.
Anthropic's model deployments for Claude Code are likely optimized for Claude Code. I wouldn't be surprised if they had optimizations like sharing of system prompt KV-cache across users, or a speculative execution model specifically fine-tuned for the way Claude Code does tool calls.
When setting your token limits, their economics calculations likely assume that those optimizations are going to work. If you're using a different agent, you're basically underpaying for your tokens.
It’s probably a mixture of things including direct control over how the api is called and used as pointed out above and giving a discount for using their ecosystem. They are in fact a business so it should not surprise anyone they act as one.
It might well be a mixture, but 95% of that mixture is vendor lock in. Same reason they don't support AGENTS.md, they want to add friction in switching.
It's very straightforward to instrument CC under tmux with send-keys and capturep. You could easily use that for distillation, IMO. There are also detailed I/O logs.
Yup. And right now I'm straight-up breaking Claude's TOS by modifying OpenCode to still accept tokens. But I only have a few days left and don't care if they ban me. I'm using what I paid for.
Anthropic has an API, you can use any client but they charge per input/output/cache token.
One-price-per-month subscriptions (Claude Code Pro/MAX @ $20/$100/$200 a month) use a different authentication mechanism, OAUTH. The useful difference is you get a lot more inference than you can for the same cost using the API but they require you to use Claude Code as a client.
Some clients have made it simple to use your subscription key with them and they are getting cease and desist letters.
