The article introduces CUGA, IBM’s open-source agent harness that handles planning, execution loops, tool calls and state management so you only define tools and prompts. It walks through a FastAPI “cloud advisor” example and shows how two dozen single-file apps share the same skeleton for quick setup, governance and scaling.

• IBM's CUGA harness lets you build agentic apps by defining only tools and prompts—planning, execution, error handling, and state management are all handled by the harness.
• The cuga-apps repo has two dozen working single-file FastAPI demos, each under 100 lines of code, covering things like a movie recommender and an IBM Cloud architecture advisor.
• Tools follow a strict success/failure envelope ({"ok": true/false, ...}) so the planner can distinguish recoverable errors from undeclared failures.
• Built-in Fast/Balanced/Accurate modes tune cost vs. latency without code changes, and the reflection step keeps multi-step runs reliable even with smaller open-weight models like gpt-oss-120b.