Open source trust economics - PRs NOT Welcome (Vercel agent factory, Latent Space)

Every governance framework I have helped build rests on an unwritten assumption: a document or other submission arriving from outside cost real effort to produce, and the effort means something. Open source has just shown what happens when that assumption fails.

GitHub made pull requests open by default eighteen years ago, on the social contract that strangers would improve your code. Latent Space reports that Flue and tldraw now automatically close external pull requests, in part because they are usually AI-generated, while Vercel's AI SDK, which serves over 20 million npm downloads a week, had more than 1,000 open issues and almost 800 open pull requests by late June. Vercel's answer was a software factory of its own agents: four weeks in, it authors 25 to 35 per cent of merged PRs and closes 70 to 80 per cent of issues. It works, honestly: a human still merges every change and the backlog is genuinely falling.

Yet Vercel's Lars Grammel prefers his own agents: "not necessarily trusting the community, because it can actually cut down your time to review." What has broken is not the quality of contributions but the economics of trusting them. A tuned internal agent is a known quantity; an external contribution is an unbounded review liability, and Vercel's security model treats every issue, pull request and comment as attacker-controlled input. The open door has become an attack surface.

Run the same arithmetic through an enterprise. A supplier who once wrote five considered tenders can submit fifty compliant ones. Grant assessors can receive 10 times as many applications, each plausible and polished. Recruiters already screen AI-written applications with AI, leaving the interview carrying the whole weight of trust. Because generation costs almost nothing while proper review costs what it always did, a channel designed for strangers acting in good faith becomes a denial-of-service attack on your own evaluation capacity.

This is no argument against AI-generated contributions; Vercel's factory is itself one such contribution, trusted because it is internal and accountable. What replaces openness as the default is a trust architecture in which verified insiders do the work and everything from outside is suspect until proven otherwise. Open source is where the mathematics arrived first. Any organisation with a public inbox is running the same equation, and those that redesign their intake before the volume arrives will still be able to judge anything.