This is exactly what frameworks like Claude Code, OpenAI Codex, Cursor agent mode, OpenHands, SWE-Agent, Devin, and others do. It definitely does allow models

This is exactly what frameworks like Claude Code, OpenAI Codex, Cursor agent mode, OpenHands, SWE-Agent, Devin, and others do. It definitely does allow models to do more. However, the high-level planning, reflection and executive function still aren't there. LLMs can nowadays navigate very complex tasks using "intuition": just ask them to do the task, give them tools, and they do a good job. But if the task is too long or requires too much information, the context length deteriorates the performance significantly, so you have to switch to a multi-step pipeline with multiple levels of execution. This is, perhaps unexpectedly, where things start breaking down. Having the LLM write down a plan lossily compresses the "intuition", and LLMs (yes, even Gemini 2.5 Pro) cannot understand what's important to include in such a grand plan, how to predict possible externalities, etc. This is a managerial skill and seems distinct from closed-form coding, which you can always RL towards. Errors, omissions, and assumptions baked into the plan get multiplied many times over by the subsequent steps that follow the plan. Sometimes, the plan heavily depends on the outcome of some of the execution steps ("investigate if we can..."). Allowing the "execution" LLM to go back and alter the plan results in total chaos, but following the plan rigidly leads to unexpectedly stupid issues, where the execution LLM is trying to follow flawed steps, sometimes even recognizing that they are flawed and trying to self-correct inappropriately. In short, we're still waiting for an LLM which can keep track of high-level task context and effectively steer and schedule lower-level agents to complete a general task on a larger time horizon. For a more intuitive example, see how current agentic browser use tools break down when they need to complete a complex, multi-step task. Or just ask Claude Code to do a feature in your existing codebase (that is not simple CRUD) the way you'd tell a junior dev.