Where they are very useful is as a documentation source for LLMs. For example, I work in infosec and often have to reference DSLs (Cobalt Strike aggressor script for example). Having a skill which is an offline index to carved up function docs, which an LLM can use without having to think, then search for, then download huge 1 page documents with all function documentation, and pollute the context… very useful.
I did create special repo that has all skills/agents/scripts and MCP configuration. All agents ( currently 3 in use: claude code, opencode, and pi ) packed in docker container, with artifacts required by project technologies, and task at hand ( planning, code review, documentation management, web design, ... ). Nothing but a small file with list of technologies committed to project.
For evaluation, there is command to record session, repository commit, and observed problems that stored in special database, so each session can be reproduced. Developer commit reports, I do analysis, refine and evaluate system.
