Opencode ought to have similar usage patterns to Claude Code, being a very similar software (if anything Opencode would use fewer tokens as it doesn't have some fancy features from Claude Code like plan files and background agents). Any subscription usage pattern "abuses" that you can do with Opencode can also be done by running Claude Code automatically from the CLI. Therefore restricting Opencode wouldn't really save Anthropic money as it would just move problem users from automatically calling Opencode to automatically calling CC. The move seems to purely be one to restrict subscribers from using competing tools and enforce a vertically-integrated ecosystem.
In fact, their competitor OpenAI has already realized that Opencode is not really dissimilar from other coding agents, which is why they are comfortable officially supporting Opencode with their subscription in the first place. Since Codex is already open-source and people can hack it however they want, there's no real downside for OpenAI to support other coding agents (other than lock-in). The users enter through a different platform, use the service reasonably (spending a similar amount of tokens as they would with Codex), and OpenAI makes profit from these users as well as PR brownie points for supporting an open ecosystem.
In my mind being in control of the tools I use is a big feature when choosing an AI subscription and ecosystem to invest into. By restricting Opencode, Anthropic has managed to turn me off from their product offerings significantly, and they've managed to do so even though I was not even using Opencode. I don't care about losing access to a tool I'm not using, but I do care about what Anthropic signals with this move. Even if it isn't the intention to lock us in and then enshittify the product later, they are certainly acting like it.
The thing is, I am usually a vote-with-my-wallet person who would support Anthropic for its values even if they fall behind significantly compared to competitors. Now, unless they reverse course on banning open-source AI tools, I will probably revert to simply choosing whichever AI company is ahead at any given point.
I don't know whether Anthropic knows that they are pissing off their most loyal fanbase of conscientious consumers a lot with these moves. Sure, we care about AI ethics and safety, but we also care about being treated well as consumers.