Tessl says 75% of its agent-written PRs merge without human review

Tessl says its engineers open more than 1,200 agent-written pull requests a week in one monorepo, and that PRs that never merged plus review-fix rounds made up over half of its agent spend. It replaced its previous AI reviewer, which the post does not name, with its own product, Tessl Code Review, which checks each PR against the standards the team already writes for its agents. Since the switch, the post says, about 75% of PRs have merged "without a human correcting the agent or discussing the engineering."

The comparison comes from one week in which both reviewers ran on every PR in the monorepo, more than 600 in total. Tessl counts 91% of its reviewer's findings as real defects, against 68% for the previous one, and 1.56 author-fixed bugs per PR against 0.75. A real defect had to be something that would misbehave in production; style and naming did not count. The post carries two caveats of its own. On an external benchmark with human-labeled defects, the two reviewers tied. And the previous reviewer was stronger on low-severity findings and caught some defects that Tessl's missed. It also reports that 8.5% of PRs went through more than five review rounds and used 47.4% of review loop spend. These are a vendor's figures about its own product, and nobody outside Tessl has reproduced them.

Why it matters: The tie on the outside benchmark is the number to notice. On Tessl's own account, its reviewer pulled ahead only on the repo where it could check work against the team's written standards. For a team deciding whether agent PRs can merge unread, that points the effort at writing down its standards before it shops for a better reviewer.