v0.7.9

October 22, 2026 · GitHub release · All changes

New features

Change published ports without recreating a sandbox. msb modify now adds, updates, and removes individual TCP or UDP mappings while keeping the rest. Apply changes with --restart or save them with --next-start. The Rust, Python, TypeScript, and Go SDKs expose the same operations. Port changes are local-only.

msb modify worker -p 8080:3000 --next-start
msb modify worker --port-rm 8080 --restart

Known conflicts are rejected before anything is saved, but ports are not reserved until startup. Change published ports Tell agents why a request was blocked. Denied HTTP requests now get a JSON 403 Forbidden response with code, message, and domain fields instead of a dropped connection. Supported secret-policy violations get the same treatment, so an agent can explain the denial or ask for access. HTTP denial responses Restrict which backends users can run. Set allowed_backends to ["local"], ["cloud"], or both in user config or managed overrides. The standalone CLI can now select cloud, and msb context list, use, and reset inspect and switch saved profiles. Backends · Context commands More control for running sandboxes.

Label changes on a running local sandbox now apply live instead of waiting for a restart. Update labels
HTTP CONNECT proxies accept Basic authentication from the CLI with --http-connect-username and --http-connect-password-env, or through the Rust SDK. The password stays on the host.
--max-inbound-tcp-connections caps active connections across published ports. Published ports
The Rust SDK adds terminal_exit() to read why a local sandbox last stopped, such as an idle timeout or a crash. Rust reference

Before upgrading

Check response status on denied requests. Code that expected a connection error may now receive 403. Set deny_response: false to close silently, or deny_response_format: text for the legacy plain-text body. JSON responses require a supporting runtime. Cloud behavior is unchanged.
Published ports no longer cap inbound connections by default. Older runtimes allowed 256. Set --max-inbound-tcp-connections to keep a limit.
Upgrade clients before relying on new settings. Older CLI and SDK versions ignore allowed_backends and can remove it when saving user config. They also drop HTTP CONNECT credentials from saved configuration.
Rust API changes. Backend::info() and default_backend_info() return MicrosandboxResult<BackendInfo>. Exhaustive GlobalConfig literals and OutboundProxy::HttpConnect patterns need the new fields. See upgrade notes.

Fixes

Commands with large output or stdin now use bounded buffers, so one slow reader no longer stalls other commands in the sandbox.
Completed published-port connections free their slots promptly, and IPv4 fallback works when IPv6 stalls.
modify rejects env entries and label keys that would stop a sandbox from booting, updates the effective value of repeated env keys, and keeps a secret’s substitution rule unless you pass a new one.
Archive restores read metadata first and defer extraction until creation, and imports no longer create duplicate catalog entries.
msb df shows a shorter summary by default; use --verbose for details.
Fixed macOS SQLite locking, relative installer paths, and Node bundled-binary resolution in paths with special characters. The guest kernel is updated to Linux 6.12.113.