refactor(domain): centralize relationship coverage interpretation

src/domain/callPath.ts

@@ -1,3 +1,4 @@
+import { relationshipCoverageLimitations } from "./relationshipCoverage.js";
 import {
   callPathInputSchema,
   callPathResultSchema,
@@ -240,15 +241,12 @@ const inspectSearch = ({
       const coverage = snapshot.evidence.relationship_coverage;
       for (const limitation of snapshot.limitations)
         limitations.push(limitation);
-      if (coverage?.status === "partial")
-        for (const limitation of coverage.limitations)
+      if (coverage !== null) {
+        for (const limitation of relationshipCoverageLimitations(coverage))
           limitations.push(limitation);
-      else if (coverage?.status === "unknown")
-        limitations.push(coverage.reason);
-      for (const diagnostic of coverage !== null && "diagnostics" in coverage
-        ? coverage.diagnostics
-        : [])
-        limitations.push(diagnostic);
+        for (const diagnostic of coverage.diagnostics ?? [])
+          limitations.push(diagnostic);
+      }
       // The requested goal is a terminal for this search. Its outgoing edges
       // cannot add a path to the goal, so its dossier limits are contextual
       // but do not make the searched start-to-goal closure incomplete.

src/domain/functionCallCoverage.ts

@@ -1,4 +1,7 @@
-import type { RelationshipCoverage } from "./relationshipCoverage.js";
+import {
+  relationshipCoverageLimitations,
+  type RelationshipCoverage,
+} from "./relationshipCoverage.js";
 import type { FunctionDossier } from "./hopperValues.js";
 import { uniqueSorted } from "./canonicalOrdering.js";
 
@@ -15,11 +18,7 @@ export const combineFunctionRelationshipCoverage = (
     { direction: "callees" as const, coverage: callees },
   ];
   const diagnostics = uniqueSorted(
-    reads.flatMap(({ coverage }) =>
-      coverage !== undefined && "diagnostics" in coverage
-        ? coverage.diagnostics
-        : [],
-    ),
+    reads.flatMap(({ coverage }) => coverage?.diagnostics ?? []),
   );
   const details = diagnostics.length > 0 ? { diagnostics } : {};
   const callersLimited = callers?.status !== "complete";
@@ -35,15 +34,9 @@ export const combineFunctionRelationshipCoverage = (
   const reasons = reads.flatMap(({ direction, coverage }) => {
     const label =
       direction === "callers" ? callerCoveragePrefix : calleeCoveragePrefix;
-    const limitations =
-      coverage === undefined
-        ? ["Provider did not report relationship coverage."]
-        : coverage.status === "unknown"
-          ? [coverage.reason]
-          : coverage.status === "partial"
-            ? coverage.limitations
-            : [];
-    return limitations.map((reason) => `${label}${reason}`);
+    return relationshipCoverageLimitations(coverage).map(
+      (reason) => `${label}${reason}`,
+    );
   });
   if (
     reads.some(
@@ -90,24 +83,11 @@ export const functionCallCoverageLimitations = (
   coverage: RelationshipCoverage | null,
   dossier: Pick<FunctionDossier, "unresolved_calls">,
 ): string[] => {
-  const limitations =
-    coverage === null
-      ? ["Provider did not report relationship coverage."]
-      : coverage.status === "unknown"
-        ? [
-            coverage.reason,
-            ...("diagnostics" in coverage ? coverage.diagnostics : []),
-          ]
-        : coverage.status === "partial"
-          ? [
-              ...coverage.limitations,
-              ...("diagnostics" in coverage ? coverage.diagnostics : []),
-            ]
-          : [];
-  limitations.push(
+  return uniqueSorted([
+    ...relationshipCoverageLimitations(coverage),
+    ...(coverage?.status === "complete" ? [] : (coverage?.diagnostics ?? [])),
     ...(dossier.unresolved_calls ?? []).map(
       ({ address, reason }) => `Unresolved call at ${address}: ${reason}`,
     ),
-  );
-  return uniqueSorted(limitations);
+  ]);
 };

src/domain/relationshipCoverage.ts

@@ -33,3 +33,19 @@ export const relationshipCoverageSchema = z.discriminatedUnion("status", [
 ]);
 
 export type RelationshipCoverage = z.infer<typeof relationshipCoverageSchema>;
+
+/** Reasons the observed relationship inventory cannot establish completeness. */
+export const relationshipCoverageLimitations = (
+  coverage: RelationshipCoverage | null | undefined,
+): readonly string[] => {
+  switch (coverage?.status) {
+    case undefined:
+      return ["Provider did not report relationship coverage."];
+    case "complete":
+      return [];
+    case "partial":
+      return coverage.limitations;
+    case "unknown":
+      return [coverage.reason];
+  }
+};