diff --git a/explorer/src/workspaces/DecisionWorkspace/DecisionWorkspace.tsx b/explorer/src/workspaces/DecisionWorkspace/DecisionWorkspace.tsx
index 601148a1..f22fb547 100644
--- a/explorer/src/workspaces/DecisionWorkspace/DecisionWorkspace.tsx
+++ b/explorer/src/workspaces/DecisionWorkspace/DecisionWorkspace.tsx
@@ -92,6 +92,7 @@ export function DecisionWorkspace() {
   const [chainLoading, setChainLoading] = useState(false);
   const [listLoading, setListLoading] = useState(true);
   const [filter, setFilter] = useState("");
+  const [error, setError] = useState("");
 
   // Tracks the active chain request so stale responses from rapid selections are ignored.
   const chainCtrlRef = useRef<AbortController | null>(null);
@@ -100,13 +101,22 @@ export function DecisionWorkspace() {
     const ctrl = new AbortController();
     setListLoading(true);
     fetch("/api/decisions", { signal: ctrl.signal })
-      .then((r) => r.ok ? r.json() : Promise.reject(r.status))
+      .then(async (r) => {
+        if (!r.ok) throw new Error(`HTTP ${r.status}`);
+        const data = await r.json();
+        if (r.status === 207) setError(data.message || "Warning: Partial success loading decisions.");
+        return data;
+      })
       .then((data) => {
         if (ctrl.signal.aborted) return;
         setDecisions(data);
         if (data.length > 0) void loadChain(data[0]);
       })
-      .catch((e) => { if (e?.name !== "AbortError") console.error(e); })
+      .catch((e) => {
+        if (e?.name !== "AbortError") {
+          setError(e instanceof Error ? e.message : "Failed to load decisions.");
+        }
+      })
       .finally(() => {
         if (!ctrl.signal.aborted) setListLoading(false);
       });
@@ -127,11 +137,16 @@ export function DecisionWorkspace() {
     setChain([]);
     try {
       const res = await fetch(`/api/decisions/${encodeURIComponent(d.decision_id)}/chain`, { signal: ctrl.signal });
-      if (!res.ok) throw new Error(`${res.status}`);
+      if (!res.ok) throw new Error(`HTTP ${res.status}`);
       const data = await res.json();
+      if (res.status === 207 && !ctrl.signal.aborted) {
+        setError(data.message || "Warning: Partial success loading chain.");
+      }
       if (!ctrl.signal.aborted) setChain(data.chain || []);
     } catch (e) {
-      if (e instanceof Error && e.name !== "AbortError") console.error(e);
+      if (e instanceof Error && e.name !== "AbortError") {
+        setError(e.message);
+      }
     } finally {
       if (!ctrl.signal.aborted) setChainLoading(false);
     }
@@ -213,6 +228,12 @@ export function DecisionWorkspace() {
       <div style={{ flex: 1, display: "flex", flexDirection: "column", overflow: "hidden", position: "relative" }}>
         <div style={{ position: "absolute", inset: 0, background: "radial-gradient(ellipse 60% 40% at 70% 20%, rgba(74,163,255,0.04), transparent 55%)", pointerEvents: "none" }} />
 
+        {error ? (
+          <div style={{ padding: 12, borderRadius: 14, color: "#ffb4c2", background: "rgba(255,157,175,0.1)", border: "1px solid rgba(255,157,175,0.18)", margin: "16px 16px 0 16px", zIndex: 2, position: "relative" }}>
+            {error}
+          </div>
+        ) : null}
+
         {selected ? (
           <div className="ws-scroll ws-padded ws-animate-in" style={{ position: "relative", zIndex: 1 }}>
             {/* Decision header */}
diff --git a/explorer/src/workspaces/EnrichWorkspace/EntityResolutionTab.tsx b/explorer/src/workspaces/EnrichWorkspace/EntityResolutionTab.tsx
index 5d1c9151..dfaf846b 100644
--- a/explorer/src/workspaces/EnrichWorkspace/EntityResolutionTab.tsx
+++ b/explorer/src/workspaces/EnrichWorkspace/EntityResolutionTab.tsx
@@ -192,6 +192,7 @@ export function EntityResolutionTab() {
   }, [threshold]);
 
   const handleMerge = useCallback(async (primaryId: string, duplicateId: string) => {
+    setScanError("");
     try {
       const res = await fetch("/api/enrich/merge", {
         method: "POST",
@@ -200,6 +201,9 @@ export function EntityResolutionTab() {
       });
       if (!res.ok) throw new Error(`Merge failed (${res.status})`);
       const data = await res.json();
+      if (res.status === 207) {
+        setScanError(data.message || "Warning: Partial merge.");
+      }
       logEvent("merge", `Merged ${duplicateId} → ${primaryId} · ${data.edges_updated ?? 0} edges redirected`, {
         primary: primaryId,
         duplicate: duplicateId,
@@ -207,7 +211,7 @@ export function EntityResolutionTab() {
       });
       setPairs((prev) => prev.filter((p) => !(p.a.id === primaryId && p.b.id === duplicateId)));
     } catch (err) {
-      console.error("[EntityResolution] merge failed", err);
+      setScanError(err instanceof Error ? err.message : "Merge failed");
     }
   }, []);
 
diff --git a/explorer/src/workspaces/LineageWorkspace/LineageDiagram.tsx b/explorer/src/workspaces/LineageWorkspace/LineageDiagram.tsx
index bd53cc14..8b3f4e0d 100644
--- a/explorer/src/workspaces/LineageWorkspace/LineageDiagram.tsx
+++ b/explorer/src/workspaces/LineageWorkspace/LineageDiagram.tsx
@@ -33,6 +33,7 @@ export function LineageDiagram() {
   const [edges, setEdges] = useState<any[]>([]);
   const [searchId, setSearchId] = useState("");
   const [activeId, setActiveId] = useState("");
+  const [error, setError] = useState("");
 
   const downloadReport = async (format: "json" | "markdown") => {
     if (!activeId) return;
@@ -70,17 +71,18 @@ export function LineageDiagram() {
 
         if (!res.ok) {
           const text = await res.text();
-          console.error(`HTTP ${res.status}: API Route missing or failed.`, text.substring(0, 100));
-          return;
+          throw new Error(`HTTP ${res.status}: API Route missing or failed. ${text.substring(0, 100)}`);
         }
 
         const contentType = res.headers.get("content-type");
         if (!contentType || !contentType.includes("application/json")) {
-          console.error("Backend returned non-JSON response (likely an HTML fallback). Check FastAPI routing.");
-          return;
+          throw new Error("Backend returned non-JSON response (likely an HTML fallback).");
         }
 
         const data = await res.json();
+        if (res.status === 207) {
+          setError(data.message || "Warning: Partial success loading lineage.");
+        }
 
         const counters: Record<string, number> = { "group_agent": 0, "group_activity": 0, "group_entity": 0 };
 
@@ -109,7 +111,7 @@ export function LineageDiagram() {
         setNodes([...xLanes, ...mappedNodes]);
         setEdges(mappedEdges);
       } catch (err) {
-        console.error(err);
+        setError(err instanceof Error ? err.message : "Failed to load lineage.");
       }
     };
     fetchLineage();
@@ -143,6 +145,12 @@ export function LineageDiagram() {
         </button>
       </div>
 
+      {error ? (
+        <div style={{ position: "absolute", top: 60, left: 14, right: 14, zIndex: 10, padding: 12, borderRadius: 14, color: "#ffb4c2", background: "rgba(255,157,175,0.1)", border: "1px solid rgba(255,157,175,0.18)" }}>
+          {error}
+        </div>
+      ) : null}
+
       {activeId ? (
         <ReactFlow nodes={nodes} edges={edges} fitView>
           <Background color="rgba(74,163,255,0.08)" gap={24} />
diff --git a/explorer/src/workspaces/ManageWorkspace/KGOverviewTab.tsx b/explorer/src/workspaces/ManageWorkspace/KGOverviewTab.tsx
index e882ba91..ce76e2bf 100644
--- a/explorer/src/workspaces/ManageWorkspace/KGOverviewTab.tsx
+++ b/explorer/src/workspaces/ManageWorkspace/KGOverviewTab.tsx
@@ -81,35 +81,40 @@ export function KGOverviewTab() {
         fetch("/api/graph/nodes?limit=500"),
       ]);
 
-      if (statsRes.ok) {
-        const statsData: KGStats = await statsRes.json();
-        setStats(statsData);
+      if (!statsRes.ok) throw new Error(`Stats fetch failed (${statsRes.status})`);
+      if (!nodesRes.ok) throw new Error(`Nodes fetch failed (${nodesRes.status})`);
+
+      const statsData: KGStats = await statsRes.json();
+      setStats(statsData);
+      if (statsRes.status === 207) {
+        setError((statsData as any).message || "Warning: Partial success loading stats.");
       }
 
-      if (nodesRes.ok) {
-        const nodesData: NodeListResponse = await nodesRes.json();
-        const nodes = nodesData.nodes ?? [];
-        setNodeTypeMap(buildTypeMap(nodes, "type"));
+      const nodesData: NodeListResponse = await nodesRes.json();
+      const nodes = nodesData.nodes ?? [];
+      setNodeTypeMap(buildTypeMap(nodes, "type"));
+      if (nodesRes.status === 207 && statsRes.status !== 207) { // Only overwrite error if not already set, or just append
+         setError((prev) => prev ? prev + " " + ((nodesData as any).message || "") : ((nodesData as any).message || "Warning: Partial success loading nodes."));
+      }
 
-        // Simulate neighbor counts via edges fetch for top-N
-        const edgesRes = await fetch("/api/graph/edges?limit=2000");
-        if (edgesRes.ok) {
-          const edgesData = await edgesRes.json();
-          const edges: { source: string; target: string }[] = edgesData.edges ?? [];
-          const degreeMap: Record<string, number> = {};
-          for (const edge of edges) {
-            degreeMap[edge.source] = (degreeMap[edge.source] ?? 0) + 1;
-            degreeMap[edge.target] = (degreeMap[edge.target] ?? 0) + 1;
-          }
-          const sorted = nodes
-            .map((n) => ({ node: n, neighborCount: degreeMap[n.id] ?? 0 }))
-            .sort((a, b) => b.neighborCount - a.neighborCount)
-            .slice(0, 10);
-          setTopNodes(sorted);
+      // Simulate neighbor counts via edges fetch for top-N
+      const edgesRes = await fetch("/api/graph/edges?limit=2000");
+      if (edgesRes.ok) {
+        const edgesData = await edgesRes.json();
+        const edges: { source: string; target: string }[] = edgesData.edges ?? [];
+        const degreeMap: Record<string, number> = {};
+        for (const edge of edges) {
+          degreeMap[edge.source] = (degreeMap[edge.source] ?? 0) + 1;
+          degreeMap[edge.target] = (degreeMap[edge.target] ?? 0) + 1;
         }
+        const sorted = nodes
+          .map((n) => ({ node: n, neighborCount: degreeMap[n.id] ?? 0 }))
+          .sort((a, b) => b.neighborCount - a.neighborCount)
+          .slice(0, 10);
+        setTopNodes(sorted);
       }
-    } catch {
-      setError("Failed to load graph overview. Ensure the server is running.");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load graph overview. Ensure the server is running.");
     } finally {
       setLoading(false);
     }
@@ -135,6 +140,12 @@ export function KGOverviewTab() {
 
   return (
     <div className="ws-page">
+      {error ? (
+        <div style={{ margin: "16px 22px 0 22px", padding: 12, borderRadius: 14, color: "#ffb4c2", background: "rgba(255,157,175,0.1)", border: "1px solid rgba(255,157,175,0.18)" }}>
+          {error}
+        </div>
+      ) : null}
+
       {/* Header */}
       <div style={{ display: "flex", alignItems: "center", justifyContent: "space-between", padding: "16px 22px", borderBottom: "1px solid var(--ws-border)", flexShrink: 0 }}>
         <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
diff --git a/explorer/src/workspaces/OntologyWorkspace/OntologyManager.tsx b/explorer/src/workspaces/OntologyWorkspace/OntologyManager.tsx
index 363de1bc..3c6de057 100644
--- a/explorer/src/workspaces/OntologyWorkspace/OntologyManager.tsx
+++ b/explorer/src/workspaces/OntologyWorkspace/OntologyManager.tsx
@@ -255,13 +255,13 @@ export function OntologyManager() {
       const params = new URLSearchParams();
       if (searchQ) params.set("q", searchQ);
       const res = await fetch(`/api/ontology/registry?${params}`);
-      if (res.ok) {
-        setEntries(await res.json());
-      } else {
-        setEntries([]);
-      }
+      if (!res.ok) throw new Error(`HTTP ${res.status}`);
+      const data = await res.json();
+      setEntries(data);
+      if (res.status === 207) flashMsg("err", data.message || "Warning: Partial success loading registry.");
     } catch {
       setEntries([]);
+      flashMsg("err", "Failed to load ontology registry");
     } finally {
       setLoading(false);
     }
diff --git a/explorer/src/workspaces/OntologyWorkspace/OntologySearch.tsx b/explorer/src/workspaces/OntologyWorkspace/OntologySearch.tsx
index 5285aad4..8e8c79c8 100644
--- a/explorer/src/workspaces/OntologyWorkspace/OntologySearch.tsx
+++ b/explorer/src/workspaces/OntologyWorkspace/OntologySearch.tsx
@@ -182,9 +182,11 @@ function DetailPanel({
     setLoading(true);
     setError("");
     fetch(`/api/ontology/entity/${encodeURIComponent(uri)}`)
-      .then((r) => {
+      .then(async (r) => {
         if (!r.ok) throw new Error("Not found");
-        return r.json();
+        const data = await r.json();
+        if (r.status === 207) setError(data.message || "Warning: Partial success loading entity.");
+        return data;
       })
       .then(setDetail)
       .catch((e) => setError(e.message))
diff --git a/explorer/src/workspaces/OntologyWorkspace/SKOSVocabularyManager.tsx b/explorer/src/workspaces/OntologyWorkspace/SKOSVocabularyManager.tsx
index d46951d5..62dff1e1 100644
--- a/explorer/src/workspaces/OntologyWorkspace/SKOSVocabularyManager.tsx
+++ b/explorer/src/workspaces/OntologyWorkspace/SKOSVocabularyManager.tsx
@@ -81,9 +81,11 @@ function ConceptDetailPanel({
     setLoading(true);
     setError("");
     fetch(`/api/ontology/skos/concept/${encodeURIComponent(uri)}`)
-      .then((r) => {
+      .then(async (r) => {
         if (!r.ok) throw new Error("Concept not found");
-        return r.json();
+        const data = await r.json();
+        if (r.status === 207) setError(data.message || "Warning: Partial success loading concept.");
+        return data;
       })
       .then(setDetail)
       .catch((e) => setError(e.message))
@@ -323,14 +325,23 @@ function SchemePanel({
   const [expanded, setExpanded] = useState(true);
   const [hierarchy, setHierarchy] = useState<ConceptNode[]>([]);
   const [loading, setLoading] = useState(false);
+  const [error, setError] = useState("");
 
   useEffect(() => {
     if (!expanded) return;
     setLoading(true);
     fetch(`/api/vocabulary/hierarchy?scheme=${encodeURIComponent(scheme.uri)}`)
-      .then((r) => (r.ok ? r.json() : []))
+      .then(async (r) => {
+        if (!r.ok) throw new Error(`HTTP ${r.status}`);
+        const data = await r.json();
+        if (r.status === 207) setError(data.message || "Warning: Partial success loading hierarchy.");
+        return data;
+      })
       .then(setHierarchy)
-      .catch(() => setHierarchy([]))
+      .catch((err) => {
+        setHierarchy([]);
+        setError(err instanceof Error ? err.message : "Failed to load hierarchy.");
+      })
       .finally(() => setLoading(false));
   }, [scheme.uri, expanded]);
 
@@ -366,6 +377,7 @@ function SchemePanel({
 
       {expanded && (
         <div style={{ paddingBottom: 8 }}>
+          {error ? <div style={errorStyle}>{error}</div> : null}
           {loading ? (
             <div style={{ padding: "10px 20px", display: "flex", alignItems: "center", gap: 8 }}>
               <Loader2 size={12} color="#4aa3ff" style={{ animation: "spin 0.8s linear infinite" }} />
@@ -412,7 +424,12 @@ export function SKOSVocabularyManager({ schemeUri }: Props) {
   useEffect(() => {
     setLoading(true);
     fetch("/api/ontology/skos/schemes")
-      .then((r) => (r.ok ? r.json() : []))
+      .then(async (r) => {
+        if (!r.ok) throw new Error(`Failed to load schemes (${r.status})`);
+        const data = await r.json();
+        if (r.status === 207) setError(data.message || "Warning: Partial success loading schemes.");
+        return data;
+      })
       .then(setSchemes)
       .catch((e) => setError(e.message))
       .finally(() => setLoading(false));
@@ -424,6 +441,7 @@ export function SKOSVocabularyManager({ schemeUri }: Props) {
 
   return (
     <div style={managerShellStyle}>
+      {error ? <div style={errorStyle}>{error}</div> : null}
       {/* Search bar */}
       <div style={skosToolbarStyle}>
         <div style={skosSearchBarStyle}>
@@ -628,6 +646,8 @@ const navLinkStyle: React.CSSProperties = {
   textAlign: "left",
 };
 
+const errorStyle: React.CSSProperties = { padding: 12, borderRadius: 14, color: "#ffb4c2", background: "rgba(255,157,175,0.1)", border: "1px solid rgba(255,157,175,0.18)", margin: "0 10px 10px 10px", fontSize: 12 };
+
 const centerStyle: React.CSSProperties = {
   display: "flex",
   flexDirection: "column",
diff --git a/explorer/src/workspaces/OntologyWorkspace/ShaclStudio.tsx b/explorer/src/workspaces/OntologyWorkspace/ShaclStudio.tsx
index 5a64ee9b..7c152d1d 100644
--- a/explorer/src/workspaces/OntologyWorkspace/ShaclStudio.tsx
+++ b/explorer/src/workspaces/OntologyWorkspace/ShaclStudio.tsx
@@ -33,7 +33,10 @@ export function ShaclStudio({ onJumpToNode }: ShaclStudioProps) {
         setRegistry(entries);
         setSelectedUri((current) => current || entries[0]?.uri || "");
       })
-      .catch(() => { /* backend unavailable — leave registry empty */ });
+      .catch((err) => {
+        if (cancelled) return;
+        setError(err instanceof Error ? err.message : "Failed to load ontology registry.");
+      });
     return () => {
       cancelled = true;
     };
diff --git a/explorer/src/workspaces/OntologyWorkspace/VersionsTab.tsx b/explorer/src/workspaces/OntologyWorkspace/VersionsTab.tsx
index f9176c32..d7188fc4 100644
--- a/explorer/src/workspaces/OntologyWorkspace/VersionsTab.tsx
+++ b/explorer/src/workspaces/OntologyWorkspace/VersionsTab.tsx
@@ -47,6 +47,7 @@ export function VersionsTab() {
   const [comparePair, setComparePair] = useState<{ v1: string; v2: string } | null>(null);
   const [compareResult, setCompareResult] = useState<Record<string, any> | null>(null);
   const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState("");
 
   const loadVersions = useCallback(async () => {
     if (!ontologyUri) return;
@@ -55,9 +56,12 @@ export function VersionsTab() {
       if (response.ok) {
         const data = await response.json();
         setVersions(data);
+        if (response.status === 207) setError(data.message || "Warning: Partial success loading versions.");
+      } else {
+        setError(`Failed to load versions (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to load versions:", error);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load versions.");
     }
   }, [ontologyUri]);
 
@@ -67,9 +71,12 @@ export function VersionsTab() {
       if (response.ok) {
         const data = await response.json();
         setProposals(data);
+        if (response.status === 207) setError(data.message || "Warning: Partial success loading proposals.");
+      } else {
+        setError(`Failed to load proposals (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to load proposals:", error);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load proposals.");
     }
   }, []);
 
@@ -79,54 +86,76 @@ export function VersionsTab() {
   }, [loadVersions, loadProposals]);
 
   const approveProposal = useCallback(async (proposalId: string) => {
+    setError("");
     try {
       const response = await fetch(`/api/ontology/proposals/${proposalId}/approve`, {
         method: "POST",
       });
       if (response.ok) {
-        alert("Proposal approved");
+        if (response.status === 207) {
+          const data = await response.json().catch(() => ({}));
+          setError(data.message || "Warning: Partial success approving proposal.");
+        } else {
+          alert("Proposal approved");
+        }
         loadProposals();
+      } else {
+        setError(`Failed to approve proposal (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to approve proposal:", error);
-      alert("Failed to approve proposal");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to approve proposal.");
     }
   }, [loadProposals]);
 
   const rejectProposal = useCallback(async (proposalId: string) => {
+    setError("");
     try {
       const response = await fetch(`/api/ontology/proposals/${proposalId}/reject`, {
         method: "POST",
       });
       if (response.ok) {
-        alert("Proposal rejected");
+        if (response.status === 207) {
+          const data = await response.json().catch(() => ({}));
+          setError(data.message || "Warning: Partial success rejecting proposal.");
+        } else {
+          alert("Proposal rejected");
+        }
         loadProposals();
+      } else {
+        setError(`Failed to reject proposal (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to reject proposal:", error);
-      alert("Failed to reject proposal");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to reject proposal.");
     }
   }, [loadProposals]);
 
   const publishProposal = useCallback(async (proposalId: string) => {
+    setError("");
     try {
       const response = await fetch(`/api/ontology/proposals/${proposalId}/publish`, {
         method: "POST",
       });
       if (response.ok) {
-        alert("Proposal published");
+        if (response.status === 207) {
+          const data = await response.json().catch(() => ({}));
+          setError(data.message || "Warning: Partial success publishing proposal.");
+        } else {
+          alert("Proposal published");
+        }
         loadProposals();
         loadVersions();
+      } else {
+        setError(`Failed to publish proposal (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to publish proposal:", error);
-      alert("Failed to publish proposal");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to publish proposal.");
     }
   }, [loadProposals, loadVersions]);
 
   const runVersionComparison = useCallback(async () => {
     if (!comparePair || !ontologyUri) return;
     setIsLoading(true);
+    setError("");
     try {
       const response = await fetch(`/api/ontology/versions/${encodeURIComponent(ontologyUri)}/compare`, {
         method: "POST",
@@ -138,11 +167,13 @@ export function VersionsTab() {
       });
       if (response.ok) {
         const data = await response.json();
+        if (response.status === 207) setError(data.message || "Warning: Partial success comparing versions.");
         setCompareResult(data);
+      } else {
+        setError(`Failed to compare versions (${response.status})`);
       }
-    } catch (error) {
-      console.error("Failed to compare versions:", error);
-      alert("Failed to compare versions");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to compare versions.");
     } finally {
       setIsLoading(false);
     }
@@ -265,6 +296,8 @@ export function VersionsTab() {
     marginBottom: "12px",
   };
 
+  const errorStyle: React.CSSProperties = { padding: "12px", borderRadius: "14px", color: "#ffb4c2", background: "rgba(255,157,175,0.1)", border: "1px solid rgba(255,157,175,0.18)", marginBottom: "16px" };
+
   return (
     <div style={containerStyle}>
       <div style={headerStyle}>
@@ -278,6 +311,8 @@ export function VersionsTab() {
         />
       </div>
 
+      {error ? <div style={errorStyle}>{error}</div> : null}
+
       <div style={sectionStyle}>
         <h2 style={sectionTitleStyle}>
           <Layers size={16} />
diff --git a/explorer/src/workspaces/OntologyWorkspace/api.ts b/explorer/src/workspaces/OntologyWorkspace/api.ts
index d6294fa7..9ad6a353 100644
--- a/explorer/src/workspaces/OntologyWorkspace/api.ts
+++ b/explorer/src/workspaces/OntologyWorkspace/api.ts
@@ -20,7 +20,11 @@ async function parseResponse<T>(response: Response): Promise<T> {
     }
     throw new Error(detail);
   }
-  return response.json() as Promise<T>;
+  const data = await response.json();
+  if (response.status === 207) {
+    console.warn("Partial Success:", data.message || "Warning: 207 Multi-Status");
+  }
+  return data as T;
 }
 
 export async function loadOntologyRegistry(): Promise<OntologyEntry[]> {
diff --git a/explorer/src/workspaces/ReasoningWorkspace.tsx b/explorer/src/workspaces/ReasoningWorkspace.tsx
index 1c700bda..f8405c26 100644
--- a/explorer/src/workspaces/ReasoningWorkspace.tsx
+++ b/explorer/src/workspaces/ReasoningWorkspace.tsx
@@ -57,6 +57,7 @@ export function ReasoningWorkspace() {
       });
       const data = await response.json();
       if (!response.ok) throw new Error(data.detail || `Status ${response.status}`);
+      if (response.status === 207) setError(data.message || "Warning: Partial success reasoning.");
       setResult(data);
       if (data.mutated) queryClient.invalidateQueries({ queryKey: ["graph", "full-load"] });
     } catch (e) {
diff --git a/explorer/src/workspaces/SparqlWorkspace/SparqlWorkspace.tsx b/explorer/src/workspaces/SparqlWorkspace/SparqlWorkspace.tsx
index 82bf90dd..dfcfa60f 100644
--- a/explorer/src/workspaces/SparqlWorkspace/SparqlWorkspace.tsx
+++ b/explorer/src/workspaces/SparqlWorkspace/SparqlWorkspace.tsx
@@ -72,7 +72,17 @@ export function SparqlWorkspace() {
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({ query }),
       });
+      if (!res.ok && res.status !== 400 && res.status !== 500) {
+         // Some specific errors may return 400/500 with JSON payload
+         if (!res.headers.get("content-type")?.includes("application/json")) {
+           throw new Error(`HTTP ${res.status}`);
+         }
+      }
       const data = await res.json();
+      if (res.status === 207) {
+        data.error = data.message || "Warning: Partial success running query.";
+      }
+
       if (data.error && data.error_line && monaco && editorRef.current) {
         // eslint-disable-next-line @typescript-eslint/no-explicit-any
         (monaco as any).editor.setModelMarkers((editorRef.current as any).getModel(), "sparql", [{
@@ -81,6 +91,7 @@ export function SparqlWorkspace() {
           endLineNumber: data.error_line,
           endColumn: 100,
           message: data.error,
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
           severity: (monaco as any).MarkerSeverity.Error,
         }]);
       }