diff --git a/crates/oa-core/src/ports.rs b/crates/oa-core/src/ports.rs
index fc8cca80..b013ca26 100644
--- a/crates/oa-core/src/ports.rs
+++ b/crates/oa-core/src/ports.rs
@@ -847,6 +847,11 @@ fn legacy_allows(e: &Element, outgoing: bool) -> bool {
     matches!(e.shared(), Some(SharedBody::Port { contract: PortContract::Legacy, legacy: Some(LegacyPortContract { direction, .. }) }) if if outgoing { *direction != PortDirection::In } else { *direction != PortDirection::Out })
 }
 fn validate_carried_contract(p: &Project, r: &Relation, port: &Element, out: &mut Vec<Issue>) {
+    // Every carried-item constraint is a subset check. An empty exchange cannot
+    // violate one, so endpoint feasibility need not scan all interface roles.
+    if r.body.items().is_empty() {
+        return;
+    }
     match port.shared() {
         Some(SharedBody::Port {
             contract: PortContract::FunctionInput { incoming_items },
@@ -1060,34 +1065,6 @@ pub(crate) fn validate_port_relation(p: &Project, r: &Relation, out: &mut Vec<Is
                     "This boundary exchange retains unresolved generic port semantics.",
                 );
             }
-            for (port, peer) in [(a, b), (b, a)] {
-                if !matches!(
-                    port_contract(port),
-                    Some(PortContract::Component {
-                        kind: ComponentPortKind::Standard,
-                        ..
-                    })
-                ) {
-                    continue;
-                }
-                for required in p.relations.values().filter(|role| {
-                    role.kind() == RelationKind::InterfaceRequirement && role.source() == port.id
-                }) {
-                    if !p.relations.values().any(|role| {
-                        role.kind() == RelationKind::InterfaceProvision
-                            && role.source() == peer.id
-                            && role.target() == required.target()
-                    }) {
-                        warning(
-                            out,
-                            required.id,
-                            "unsatisfied_interface_requirement",
-                            "target",
-                            "The connected partner has not declared this required interface as provided.",
-                        );
-                    }
-                }
-            }
         }
         RelationBody::PortAllocation { source, target } => {
             let (Some(component), Some(function)) =
@@ -1167,6 +1144,49 @@ pub(crate) fn validate_port_relation(p: &Project, r: &Relation, out: &mut Vec<Is
         _ => {}
     }
 }
+/// Whole-model advisory checks. Missing peer declarations are warnings, so they
+/// must not make endpoint feasibility scan the relation graph per candidate.
+pub(crate) fn validate_boundary_interface_requirements(
+    p: &Project,
+    r: &Relation,
+    out: &mut Vec<Issue>,
+) {
+    let RelationBody::BoundaryExchange { source, target, .. } = &r.body else {
+        return;
+    };
+    let (Some(a), Some(b)) = (p.elements.get(source), p.elements.get(target)) else {
+        return;
+    };
+    for (port, peer) in [(a, b), (b, a)] {
+        if !matches!(
+            port_contract(port),
+            Some(PortContract::Component {
+                kind: ComponentPortKind::Standard,
+                ..
+            })
+        ) {
+            continue;
+        }
+        for required in p.relations.values().filter(|role| {
+            role.kind() == RelationKind::InterfaceRequirement && role.source() == port.id
+        }) {
+            if !p.relations.values().any(|role| {
+                role.kind() == RelationKind::InterfaceProvision
+                    && role.source() == peer.id
+                    && role.target() == required.target()
+            }) {
+                warning(
+                    out,
+                    required.id,
+                    "unsatisfied_interface_requirement",
+                    "target",
+                    "The connected partner has not declared this required interface as provided.",
+                );
+            }
+        }
+    }
+}
+
 pub(crate) fn validate_exchange_allocation(p: &Project, r: &Relation, out: &mut Vec<Issue>) {
     let (Some(boundary), Some(work)) = (p.relations.get(&r.source()), p.relations.get(&r.target()))
     else {
diff --git a/crates/oa-core/src/validation.rs b/crates/oa-core/src/validation.rs
index 278240a5..80eb720b 100644
--- a/crates/oa-core/src/validation.rs
+++ b/crates/oa-core/src/validation.rs
@@ -643,6 +643,7 @@ pub fn validate(p: &Project) -> Vec<Issue> {
         text(&mut out, r.id, "name", &r.name);
         text(&mut out, r.id, "description", &r.description);
         validate_relation(p, r, &mut out);
+        crate::ports::validate_boundary_interface_requirements(p, r, &mut out);
         validate_relation_context(p, r, &mut out);
     }
     for (key, d) in &p.diagrams {
@@ -2010,7 +2011,10 @@ fn relation_path_exists(p: &Project, kind: RelationKind, from: Id, to: Id) -> bo
 fn validate_relation(p: &Project, r: &Relation, out: &mut Vec<Issue>) {
     let (source, target) = r.body.endpoints();
     for id in crate::references::relation_references(r) {
-        if !p.contains(id) {
+        // Most relation references name elements. Avoid constructing all model
+        // identities per endpoint while retaining the general lookup semantics
+        // for other record kinds and malformed map keys.
+        if !p.elements.get(&id).is_some_and(|element| element.id == id) && !p.contains(id) {
             error(
                 out,
                 r.id,