If your coding agent keeps turning a small fix into a new framework, start with DietrichGebert/ponytail, the day’s top project by star events. It is a set of instructions you add to the agent’s prompt, telling it to look for existing code to reuse before inventing an abstraction, and to keep validation and error handling instead of silently dropping them. A sensible first test: give your agent a task you have already seen it over-engineer, and compare the diff against the usual behavior. For a messier problem, chopratejas/headroom compresses logs, tool outputs and retrieved documents before they reach the model. Try it on a real session where long repetitive output eats your context window, then check the compressed version still keeps the details your task depends on, since that trade-off is the whole point.
For a different failure mode, mattpocock/skills is worth a look. Its highlight is a small skill that stops the agent from coding and asks you detailed questions first, which suits anyone tired of watching an assistant confidently build the wrong thing. Pick that one skill rather than adopting the whole collection, adapt the questions to your project, and reuse the same workflow on similar tasks. If you are torn, pick ponytail when your agent overcomplicates, headroom when your agent gets flooded with input, and the questioning skill when it builds before understanding.