Sandcastle fits best when...
- You are building custom coding-agent infrastructure in TypeScript.
- The sandbox primitive is the important part.
- The surrounding product will be built in-house.
Sandcastle is for building sandboxed coding agents. ProPR is the process around them.
Sandcastle is a TypeScript library for running coding agents in isolated sandboxes. That makes it a useful infrastructure-level comparison. ProPR wraps the same isolated work in a product path: plans, tasks, pull requests, GitHub comments, logs, and follow-up commits.
vs
Sandcastle
The boundary
Sandcastle is a library for building agent infrastructure. ProPR is a self-hosted application for shipping planned AI-generated changes.
Current tool surfaceEditor, hosted workspace, review tool, or trackerWork starts where that product keeps its strongest context.
ProPR pathPlan → isolated workspace → GitHub PR → follow-up commitThe pull request and its review conversation preserve the shared history.
Sandcastle exposes a lower-level primitive for building an agent system: run coding agents in isolated environments and decide what to do with the output.
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. The opinionated workflow gives an engineering organization a system it can operate directly, with less library-level flexibility.
ProPR fits best when...
- The desired output is a planned, reviewed pull request.
- Isolation should be part of a broader PR path with logs and recovery.
- GitHub comments should trigger follow-up commits without custom glue code.
Sandbox library versus PR product.
| Question | Sandcastle | ProPR |
|---|---|---|
| Build custom agent infrastructure | Yes | No |
| Ready plan-to-PR product | No | Yes |
| Isolated agent execution | Yes | Yes |
| GitHub comments trigger follow-up commits | Custom | Yes |