Across the industry, the conversation around agents is shifting from "prompt engineering" to "harness engineering."
In its official article Harness Engineering, OpenAI argues that as model quality keeps improving, the real ceiling for an agent is no longer set by a single prompt, but by the full operating layer around the model. Anthropic, in Building Effective Agents, emphasizes that effective agents usually come from simple, composable, and continuously improvable patterns. In Claude Code's product design, long-lived instructions, Skills, Subagents, and MCP are all treated as part of the agent's execution shell. LangChain has likewise pushed middleware and context engineering as key control layers for the agent loop.
That is exactly where XpertAI 3.9.0 comes in. This release turns that thinking into a more complete agent workspace through ClawXpert + Skills.