OpenAI's GPT 5.5 is one of the most capable models available for agentic coding - writing code, using tools, running commands, and iterating on complex tasks autonomously. In this guide, you'll learn how to set up GPT 5.5 in AgentOne and start using it for agentic coding workflows. What Is Agentic Coding? Agentic coding is when an AI model doesn't just suggest code, it actively writes, runs, debugs, and iterates on code using tools. Instead of copy-pasting snippets from a chatbot, you give the agent a task and it handles the implementation end to end. GPT 5.5 excels at this because of its strong tool use capabilities, large context window, and ability to follow multistep instructions reliably. Prerequisites AgentOne desktop app installed An OpenAI API key with access to GPT 5.5 If you don't have an OpenAI API key yet, head to platform.openai.com to create one. Step 1: Open Provider Settings Launch AgentOne and open Settings . Navigate to the Provider section.…