Function phase_workers_unprovided_capabilities 

pub fn phase_workers_unprovided_capabilities(
    target: BuildTarget,
    parsed: &[ParsedFile],
    groups: &BTreeMap<String, Vec<usize>>,
    kinds: &BTreeMap<String, UnitKind>,
    unit_tables: &HashMap<String, UnitTable>,
    errors: &mut ErrorSink,
)

#1822: on the Workers target, a capability a context declares and requires (given, on a service or agent handler or a provider) needs a provider in that context. A Worker’s composition root builds every capability its handlers are given, so one with no provider left compose passing {} where the capability was required (TS2345): the bundle built and the Workers build didn’t. On the bundle target the host may supply it through __makeSurface(deps), so the check is Workers-only, like phase_secrets_computed_name. A capability from another unit (flattened or qualified) is that unit’s to provide, and exports capability already requires its provider (bynk.exports.capability_not_provided).