Install ProPR, or skip the server
Run npm install -g propr-cli and propr setup on a Linux Docker host (quickstart). ProPR Hosted runs a dedicated instance for you when you would rather not run one.
ProPR: the plan-to-PR alternative to scripting Sandcastle
Sandcastle is a TypeScript library for running coding agents in isolated sandboxes from your own scripts and pipelines. ProPR wraps the same work in a product: plans, pull requests, GitHub comments, and follow-up commits.
vs
Sandcastle
Library or application
Sandcastle is a library for building agent infrastructure. ProPR is a self-hosted application for shipping planned AI-generated changes.
Sandcastle pathScript → sandboxed agent run → commits merged into your local checkoutNo pull request creation and no handling of PR comments.
ProPR pathPlan → isolated workspace → GitHub PR → follow-up commitPlans, pull requests, and comment-driven follow-ups, with no glue code.
Switch from Sandcastle to ProPR.
What you keep: your GitHub repositories and review process, the agent logins Sandcastle already used, and your TypeScript for anything outside the PR loop.
The same ideas, ProPR's names
| Sandcastle | ProPR |
|---|---|
| Sandbox run | Task in an isolated workspace |
Issue fetched through gh | AI label on the issue |
| Commits merged into your local checkout | Pull request on the branch ProPR pushes |
| Your script's retries and logs | Task record with live log and usage |
| Claude Code, Codex, Copilot, Cursor, OpenCode, Pi | Claude Code, Codex, Antigravity CLI, Mistral Vibe, OpenCode |
From zero to the first pull request
Add the same repository and sign in your agent
Open the web UI, sign in with GitHub, and add the repository. Sign in the agents your scripts already used.
Start the first task and approve the plan
Add the AI label to the issue your script would have fetched, then approve the plan.
Review the pull request in GitHub
Review the diff the way you review any pull request. A plain comment on it becomes the next commit on the same branch; /review posts scored findings and /fix applies them. The follow-up playbook walks one comment to its commit.
What stays with Sandcastle: Sandcastle is a library you embed in your own TypeScript and run in Bubblewrap, Seatbelt, E2B, Modal, or Vercel sandboxes; ProPR is an application that isolates each task in a Docker workspace on your host.
Sandcastle, published by Matt Pocock as @ai-hero/sandcastle under the MIT license, exposes one primitive: run Claude Code, Codex, Copilot, Cursor, OpenCode, or Pi inside a sandbox such as Bubblewrap, Seatbelt, Docker, Podman, E2B, Modal, or Vercel, then merge the resulting commits back into your local checkout. It fetches issues from GitHub Issues through the gh CLI, and everything after the run stays local: no pull request creation, no handling of PR comments.
ProPR packages that primitive as an open-source application (Apache 2.0). It handles the full path from request to plan, isolated implementation, pull request, GitHub feedback, and follow-up commits. You trade library-level flexibility for an opinionated workflow you operate from day one.
Sandcastle fits best when...
- You are building custom coding-agent infrastructure in TypeScript.
- The sandbox primitive is what you need, in a script or a CI pipeline.
- You build the surrounding product in-house.
ProPR fits best when...
- You want a planned, reviewed pull request.
- Isolation is one part of a PR path with logs and follow-up commits.
- GitHub comments trigger follow-up commits with no custom glue code.
Sandbox library versus PR product.
| Question | Sandcastle | ProPR |
|---|---|---|
| License | MIT | Apache 2.0 |
| Build custom agent infrastructure | Yes | No |
| Ready plan-to-PR product | No | Yes |
| Isolated agent execution | Yes: Bubblewrap, Seatbelt, Docker, Podman, and cloud sandboxes | Yes, isolated workspace per task |
| GitHub comments trigger follow-up commits | No; merges are local and there is no PR integration | Yes |
Verified November 2026: Sandcastle repository, Sandcastle docs.