What Is Tenex's Meta-harness?

CJ Hess describes Tenex's meta-harness, the engineering workflow used for long-running tasks. It began as a standard set of skills and became structured documentation in a repo, plus a command-line tool the models use to drive the work: a plan, a visualization, a client readout, and the other steps around writing the code, done the same way across the team.

A canonical plan still has a shared shape, with less of that structure enforced as the models have improved. After the plan, agents log their decisions and what they are doing, and the record is checked into Git with the code. He prefers the HTML picture books the agents produce to markdown. The code can hold the memory of a codebase, and the checked-in notes still keep why a decision was made and what was said. That context lives in the repo rather than in someone's head, so the agents are not waiting to be handed everything up front.

Average story points per engineer per month are about double this year. Alex Lieberman marks that stretch from an Opus 4.5 moment in December through Opus 5.5.