Do you need to build your own agent harness?

Builders disagree. Shubham Saboo explains frameworks (you design the loop) versus harnesses like Claude Code and Codex (working agents you bring instructions and skills to); Matt Shumer argues custom harness engineering is usually unnecessary; LangChain's Harrison Chase says many problems are solved but new ones keep appearing. These are opinions.

Why it mattersFor most businesses: start with an existing harness, invest in clear instructions and skills, and build your own only when you hit a limit you can name.

Curated by Sara Simeone as part of our human editorial coverage. The original sources are linked below; curation is distinct from a Hype or Fact? assessment.

How we knowCompany figures are labelled as their own claims; anything we couldn't verify is labelled as a report or a claim.