OpenAI's most powerful feature. ChatGPT Agent Mode handles multi-step tasks autonomously — booking flights, writing code, managing files. We tested it for 2 weeks. Here is what actually works.
ChatGPT Agent Mode is OpenAI's answer to the autonomous AI agent trend that exploded in early 2026. Rather than answering questions, Agent Mode executes tasks — browsing the web, writing and running code, managing files and completing multi-step workflows without requiring you to stay engaged throughout. The mode is available to ChatGPT Plus and Pro subscribers and uses a combination of GPT-4o and specialised tool-calling infrastructure. In our two weeks of testing, the most impressive demonstrations were travel planning that required browsing multiple sites and price-comparing, and code debugging sessions where Agent Mode wrote tests, ran them, identified failures and fixed the code across multiple files autonomously.
We ran 30 real tasks through Agent Mode across three categories. Straightforward web research and compilation: worked excellently — compiling competitor pricing from 10 websites into a structured report took 4 minutes and required zero manual steps. Multi-step code tasks: worked well on clear requirements, struggled on ambiguous tasks. The agent would sometimes go in the wrong direction for several steps before self-correcting or getting stuck. File management and organisation: worked for simple tasks, required careful permission setup to handle sensitive directories. The key finding: Agent Mode excels when the task is well-defined with clear success criteria. It struggles with judgment calls that require domain expertise or understanding of business context.
Three agent tools, three different use cases. ChatGPT Agent Mode is the most accessible — no setup, works inside the ChatGPT interface you already use, no API costs. OpenClaw is the most powerful for device-level automation — it runs locally, accesses your entire system and is free. Devin is the most capable for software engineering specifically — it reads tickets, writes tests and opens PRs autonomously but costs significantly more. For developers who want to try agents without setup complexity or additional cost, ChatGPT Agent Mode is the obvious starting point. For serious autonomous coding, Devin still leads.
Before using Agent Mode on professional work, understand what permissions you are granting. Agent Mode can browse the web on your behalf — any websites it visits may log that a ChatGPT agent visited. For file management tasks, only grant access to the specific directories the task requires. For code execution tasks, Agent Mode runs code in an isolated sandbox by default — your local machine is not at risk. The most important precaution: review the plan Agent Mode outlines before approving execution for any high-stakes task. The plan display feature lets you verify the approach before anything happens.
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