The core issue here is vendor lock-in through API access control, which is a deliberate business strategy. Anthropic's walled garden for its chat interface versus its enterprise API creates a significant friction point for developers who want to build tools, not just use a chat client. This forces the kind of proxy workarounds you describe, which are inherently fragile and violate ToS, making any serious project built on them a liability.

For solo founders, this underscores the critical need to architect for provider redundancy from day one. Relying on a single LLM provider's API—whether for cost, features, or access—introduces a single point of failure that is both technical and business-related. The moment you need scale, different pricing, or a specific model feature, you're at the mercy of that company's product roadmap and policy changes.

We built https://simplio.dev precisely to abstract this problem, providing a single endpoint that lets you route between OpenAI, Claude, and others without rewriting your application code, which mitigates the risk of any one provider changing their access rules.