Runtime changelog, 1 November 2026

What shipped in Runtime Cloud on 1 November 2026: files: watches work in sandboxes created from the default image; CI/CD: always run a pull request's own tests; parallel forks no longer return 503 busy while a snapshot copy arrives; and CI/CD checks every push of the branches you list.

Files: watches work in sandboxes created from the default image

POST /v1/sandboxes/{id}/files/watches (and files.watch() in the SDKs) returned 500 watch_failed ("The watch exited while starting") in sandboxes created from the default image. A watch now runs in every image, and when one fails to start, the error message includes the exit code and the reason the sandbox reported.

CI/CD: always run a pull request's own tests

A split step with own: true (split: { files: "**/*.test.{ts,tsx}", own: true }) runs the test files a change adds or changes that no other step's split names. With such a step in runtime.yml, a pull request that adds or changes a test file no step runs (any language: TypeScript and JavaScript, Python, Go, or a Rust crate's files) fails with a tests not run job that lists each file and the reason. Configs without an own step are unchanged.

Parallel forks no longer return 503 busy while a snapshot copy arrives

When a snapshot's own server was full, creating many sandboxes from that snapshot at once could return 503 busy ("Cloud is busy; retry"). It happened when a create joined a copy of the snapshot that was arriving on another server. These creates now succeed, and the copy finishes arriving alongside them.

CI/CD checks every push of the branches you list

Add pushes: [{ branch: next, steps: [...] }] to the production branch's .runtime/checks.yml to check each push of a branch that has no pull request of its own, such as a staging branch. Each such check runs only the named steps, appears on GitHub as runtime @ <branch> rather than runtime, and once started it runs to its own verdict instead of being replaced by a newer push.