Yogendra Miraje describes FactSet's move from proprietary blueprints to an open skills format. He separates prompts, which define an agent's role, from tools, which determine its connections, and skills, which describe how tasks should be completed.
His minimal harness combines a registry, system prompt, file-reading tool and agent loop. A financial-research example demonstrates on-demand instructions and distinct HTML or PDF routing. Miraje recommends organizing skills around user intent rather than underlying datasets.
A model upgrade broke unchanged skills because important instructions appeared late in the file. That example motivates model-specific evaluation, named maintainers, tool access boundaries and versioning. For larger libraries, he discusses retrieval and hierarchy while framing governance as practical maintenance rather than unnecessary bureaucracy.
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