One API Key for 600+ AI Models: How I Simplified My AI Workflow with an Open-Source Agent

I use AI models every day - Claude for coding, GPT for writing, DeepSeek for reasoning, Gemini for quick lookups. Each one has its strengths, and I want access to all of them. But here's the problem: every provider means a separate account, a separate API key, separate billing. Managing five different API keys across different projects gets old fast. I recently found a setup that solved this for me: an open-source AI agent paired with an API gateway. One key, one config, access to everything. Here's how it works.