hosted-agents

Pre-build environment images on a 30-minute cadence with dependencies installed and caches warmed, then maintain a pool of pre-warmed sandboxes. Start warming a sandbox predictively when the user begins typing, so setup completes before they submit their prompt.

Use GitHub App installation tokens for repository cloning inside the sandbox, but create PRs with the prompting user's OAuth token via the API layer. Set git config user.name and user.email to the prompting user's identity so commits are attributed to them, not the app.

Yes, allow file reads immediately while blocking writes until synchronization finishes. In large repositories, incoming prompts rarely touch recently changed files, so 30-minute read staleness is safe for research while write blocking prevents conflicts.

Modal provides sandboxes with near-instant startup and filesystem snapshots, while Cloudflare Durable Objects handle per-session state with WebSocket hibernation. The patterns in this Skill are infrastructure-agnostic and adapt to providers like Fly.io as well.

Work is lost when sandboxes are recycled or time out before results are extracted. Always snapshot the filesystem before termination and build explicit extraction steps into teardown: push branches, create PRs, and return file contents before letting the sandbox die.

Skip hosted infrastructure when designing the autonomous research loop, novelty gates, or merge boundaries, which belong to harness engineering. Also avoid it when choosing agent topology without runtime concerns or when managing file-backed state within an existing session.