Function phase_workers_provider_agent_cross_context 

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

#2355 follow-up: on the Workers target, a context may not require a capability whose provider, in another context, constructs that context’s agents. The consumer’s composition root builds the provider in-process and hands it the consumer’s own env, which binds only the consumer’s Durable Object namespaces: tsc rejects the build, and strip-only bynk dev quietly falls back to agent state held in the isolate. The capability can be reached through any given the consumer’s compose instantiates — a service or agent handler’s, or a local provider’s, transitively — so the walk is collect_given_closure’s, reported once per provider at the first given that reaches it. On the bundle target the whole program shares one process and the agent factory takes only the key, so the check is Workers-only, like phase_workers_unprovided_capabilities.