Pinrail gives coding agents a desktop inbox for work that needs a human decision before it continues. Instead of approving a long terminal message wholesale, you can accept or reject individual proposed code-review comments, choose list items, annotate a document, or mark up an image. The app returns the structured decision to the waiting agent.
- Interface: An agent that can run shell commands submits a JSON payload with a review type:
pinrail submit code-review --title "Review webhook fix" --data findings.json --wait. The CLI blocks until you decide, then prints Markdown (or JSON with--json); its exit status distinguishes approval from discard. Plugins define the input/output schemas and the review UI. - Setup: Install the desktop app from the downloads page on macOS or Linux. Its setup installs the CLI, connects a skill to supported agents, and adds core review plugins. The first-review guide walks through a list review; custom plugins can be built with a manifest, two JSON schemas and an HTML view.
- Access and cost: The project says it is free, Apache-2.0 licensed, and local-only: the API listens on loopback and reviews live on your machine. The initial app release was October 6; the October 7 point releases fixed interface details and adjusted plugin SDK installation.
Limit: This is not an automatic safety gate. You must tell each agent when to submit a review, and an agent that skips that instruction can still act without Pinrail. Windows support is not available yet; the project itself warns that it is early and may have rough edges. This is a documentation-based look, not a hands-on test.
The Show HN launch discussion includes the author’s explanation of the original use case: accepting some proposed PR comments while rejecting or editing others before anything is posted.