LLMs are great at creating plans but terrible at following them. I've seen agents claim to create 5 files but only make 2, repeat API calls 3x, skip error handling, then report success anyway. The fix: treat execution like todo management—track every step, block the agent if it tries tools not in the current step, and verify completion (don't trust its word, actually check if the file exists). This plus guardrails and git-like versioning improved the reliability siginificantly

If the plan is too big to fit into context or requires too much attention it overwhelms the llm. You need to decompose into tasks and todos aggressively.