v0.28.0

Add and remove named launcher copies on a running stack, with steadier instance health and safer concurrent stack changes.

Released on September 14, 2026

Component axes no longer accept default or optional; add a deployments entry { <axis>: "<option>" } to pick which option runs, and use cardinality: "zero_or_one" in place of optional.
message_format no longer accepts the type aliases float, double, and str; use f32, f64, and string instead.

Declare a component axis with cardinality: "zero_or_more" to run its options as named copies you start, add, and remove independently under one launcher.
peppy stack join OPTION -i NAME adds a copy to a running stack, selecting its axes with --with, its machine with --place, and per-instance overrides with --set-arguments.
peppy stack remove NAME stops one copy and drops it from the stack, leaving every other copy and the stack's own nodes running.
peppy stack list and peppy stack list --json report each copy's option, host, selection, and instances.
peppy stack resolve previews a copy joined onto a launch with --join, --join-name, --join-with, and --join-set-arguments.
peppy stack reset --federated clears the launch from every machine it reached.
Fragments can declare their own component axes and reference other fragments across directories within a repository.
Constraint and adjustment when, requires, and forbids conditions accept a list of option names per axis, matching any of them.

A running instance is flagged unhealthy only after three consecutive missed health probes, and returns to healthy on the first probe it answers.
peppy node add, build, run, stop, and remove serialize with stack operations: refused while one holds the stack, and cancelled when stack reset runs after a cleanup window.
Cancelling a peppy node add, build, run, stop, or remove now stops the work on the daemon instead of letting it finish unattended.