MIT course 6.S950 updates Lecture 5 on agent harness design and observability

MIT course 6.S950, Agency with AI, has updated its Lecture 5 on the agent harness, according to a post by Meng Shao (@shao__meng) on X dated October 21, 2026.

The lecture uses a 300-line teaching agent called Baby Anigans to show how the loop of LLM, tools and checks shapes results.

The lecture argues that passing checks does not prove an answer is complete. It also says vendors increasingly encrypt parts of the harness, which reduces transparency. The source describes these claims as the lecture's argument and reports no further evidence.