How to Build a Docs Update Agent With Next.js

Building docs update agent starts with a clear trigger and ends with a handoff a person can check. The steps below define that path, and the code shape under them shows how one run holds together.

1. 1Define the trigger: issue, PR, failed CI job, docs change or support ticket.
2. 2Limit tool access to the files and systems the agent needs.
3. 3Add a plan step before writes.
4. 4Run checks and produce a short reviewer handoff.
5. 5Log the prompt, changed files, commands and result.

type AgentJob = {
  task: string;
  context: string[];
  allowedTools: string[];
  checks: string[];
  handoff: "diff" | "comment" | "pull_request";
};

Start with allowedTools. I'd say it's the field people end up regretting, though I'll admit that's a guess from a small sample. The pull is to grant broad access while you're building, because narrowing it is fiddly and everything works either way when you're sitting there watching. An agent running unattended with repo-wide write and a shell is a genuinely different risk than one that can edit three paths and run a single command, and you find out which one you built on the run where something goes wrong.

handoff is what decides whether anyone trusts the thing. Returning a diff keeps a person in front of it before anything lands, which is the right default while you're still learning how the agent behaves on your codebase. Opening a pull request is that same gate with better ergonomics, once you've earned the confidence. A comment is the lightest option and suits agents that only diagnose. What none of them should do is merge — not until the commands in checks are ones you'd have run yourself anyway.

Most failures here are not exotic. They come from giving the agent too much room, or trusting a "done" that no test ever proved.

Scope bites earliest. Give an agent a vague task and it will go and find related work to do, which reads as initiative right up until you're staring at a diff across twenty files with no idea which changes were the point. A better model doesn't fix this. A narrower task does: name the files, name the behaviour that should change, say what's out of bounds.

Weak checks bite latest, and hardest. An agent reports success from its own reading of its own work, and it isn't lying when it does that — it just has nothing external telling it otherwise. Maybe the better way to put it is that if the only thing between the agent and your main branch is its own summary, you don't have a review step at all, you have a formality with a nice interface. Give it a command whose exit code you trust, and let the run fail when that command fails.

Attach a trigger to a cloud agent so it runs on its own. Automations support pull-request events (opened, merged, draft), Slack messages on a keyword in a public channel, Linear, and PagerDuty. The natural fit for docs is the PR-merge trigger: on every merge, a cloud agent reads the changed code and updates the docs.

Yes. With Cursor integrated into Slack, the whole loop runs in a thread with a human in it. A worked example: there were no docs for an AWS Bedrock integration. The PM dropped that into Slack, Cursor read the code and created the docs, an engineer replied in-thread flagging two wrong things, Cursor was told over the same thread to fix them, and it shipped. Start to finish in 15 minutes, entirely over Slack.

Whoever hears the customer first. The old path is slow: support finds a doc gap, files a ticket, a technical writer eventually works it. That over-the-fence handoff stalls the feedback loop. With the docs open in their own Cursor workspace, support can check whether something is documented, make the change, render the doc site to review, and open a PR off the same customer interaction.

Merged, for docs. The pull-request trigger covers opened, merged and draft, and opened is tempting because the docs draft would then be ready at the same time as the code review. A pull request under review is still moving, though, so docs written against its first version describe behaviour the reviewers may have talked the author out of.

The cost is not the wasted run. It is a doc draft that reads as authoritative, sitting in the review channel beside the ones that are correct, with nothing on it to say which version of the code it was written from. Merge is a settled state. Waiting for it is the difference between one draft and a queue of drafts you have to re-check.

That the site still builds and whatever link checking you run stays green. Not that a sentence in it is true.

Which is where the general advice about handing the agent a command whose exit code you trust runs out of road. There is no exit code for accuracy in prose, so the check has to be a person, and the design problem is how cheap you can make that person's pass.

The Slack loop above is the shape worth copying for exactly that reason. The agent drafted, an engineer read it in the thread and named the two things that were wrong, the correction went back over the same thread, and it shipped inside fifteen minutes. A person was the check the whole way, and it still only took a quarter of an hour.

Because low-risk here is a claim about who should be allowed to edit, not about whether anyone should read it first. Letting support open doc pull requests off a customer conversation is cheap and obviously right. Letting an agent publish unread is a different bet, and I'd guess a confidently wrong page costs more support load than the gap it filled.