Inferable

Inferable is an open-source platform for creating AI agents and workflows. It explicitly mentions building reliable AI workflows, integrating with existing codebases, APIs, and data, and providing LLM primitives. It supports workflow versioning, managed state, observability, and on-premise execution, aligning well with the concept's focus on internal tools and automation. While it doesn't explicitly mention a drag-and-drop UI builder, its focus is on programmatic workflow definition, which is a valid approach for internal tools.