testdriver:agent

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The TestDriver agent is an AI teammate in your GitHub repository. It is code review that runs your app. It does not only read a diff and guess what can break. It starts a real sandbox, controls the real app, and reports what really happens.

Scope: it only builds and maintains tests

The agent has one purpose. It does one thing: it writes, debugs, fixes, and keeps automated tests with TestDriver. It reviews pull requests. It writes and runs a test against the change. It does not do work that is not in scope. It does not edit your application code, fix product bugs, answer other programming questions, or act as a general coding assistant.

How it behaves depends on the surface

The agent reacts to three different GitHub surfaces. Its behavior is different on each one.

Surface	Trigger	What it does
Pull request opened	Automatic (no mention)	Silent, evidence-based code review
Issue opened	Automatic (no mention)	Onboarding / test-building
@mention (issue or PR)	You mention the bot	Interactive, chatty conversation

Pull requests — automatic code review

When a pull request is opened, the agent reviews it automatically. Nobody has to ask.

• The review is the deliverable, not chatter. No person asks for an automatic review. Thus the agent stays quiet while it works. It posts a single review comment at the end. It does not put many inline threads across the diff. It does not tell each step.
• It runs the change when it can. Its default first move is to start a session, work out what the PR changes from a user's point of view, and write and run a TestDriver test that exercises exactly that. A bug it watched happen is far more valuable than one it inferred.
• Findings are labeled by how they were found. Each finding is marked observed (proven by actually running the change) or suspected (reasoned out from reading the diff). If the installation isn't signed in to TestDriver, the agent can't run anything, so it reviews by reading and marks every finding suspected.
• It focuses on real bugs. Logic errors, regressions, broken edge cases, mishandled errors — not style, naming, or "consider extracting this."
• Zero findings is a good review. If the change looks correct, it says so in a sentence. If there's nothing worth reviewing (only lockfiles, generated files, or formatting), it posts nothing at all.
• It comments, it never blocks. The review is always a COMMENT — it never approves and never requests changes, so it can't gate a merge.

It also fires a native GitHub Check Run for the PR's TestDriver suite, and re-runs that check on every push (not a full re-review — push more commits and @mention the agent if you want it to review again).

<Note> The agent never reviews its own pull requests. PRs opened by the bot are skipped, so it won't wake itself up to review the tests it just committed. </Note>

Issues — onboarding and test building

When an issue is opened, the agent treats it as a cue to help you build a test.

• If the issue describes a task, it acts on the request — writing or debugging the test you asked for.
• If the issue is empty, it introduces itself, explains that it writes and debugs computer-use tests, and walks you through signing in to TestDriver and creating your first test.
• It finishes by opening a pull request with the test it wrote.

@mentions — interactive conversation

Mentioning the bot (on either an issue or a PR) starts a solicited, interactive turn. Because you asked directly, the agent is chatty: it posts progress updates, shows you screenshots of what's happening in the sandbox, and answers follow-ups in the thread.

On a PR, an @mention overrides the silent auto-review behavior — you'll see the full play-by-play instead of just the final review comment.

You can also manage the agent from a comment:

• @bot logout (or "sign out") revokes the installation's shared TestDriver sign-in and tears down the live sandbox, so the next mention will prompt whoever responds to sign in again.

Signing in

Reading a diff needs nothing, but running the app needs a TestDriver session, which requires the installation to be signed in. Sign-in state doesn't decide whether the agent reviews — it decides how good the review gets. A signed-out install still gets its bugs caught from reading the code; signing in upgrades findings from suspected to observed.