diff --git a/lib/components/base-components/NormalComponent/NormalComponent.ts b/lib/components/base-components/NormalComponent/NormalComponent.ts
index 99534b930..8d3a1753b 100644
--- a/lib/components/base-components/NormalComponent/NormalComponent.ts
+++ b/lib/components/base-components/NormalComponent/NormalComponent.ts
@@ -18,6 +18,7 @@ import {
   point3,
   rotation,
   schematic_manual_edit_conflict_warning,
+  unknown_error_finding_part,
 } from "circuit-json"
 import { decomposeTSR } from "transformation-matrix"
 import Debug from "debug"
@@ -1443,8 +1444,37 @@ export class NormalComponent<
       }),
     )
 
-    // Convert "Not found" to empty object before caching or returning
-    const supplierPartNumbers = result === "Not found" ? {} : result
+    // Validate the result format
+    if (typeof result === "string") {
+      // Check if it's an HTML error page or "Not found"
+      if (result.includes("<!DOCTYPE") || result.includes("<html")) {
+        throw new Error(
+          `Failed to fetch supplier part numbers: Received HTML response instead of JSON. Response starts with: ${result.substring(0, 100)}`,
+        )
+      }
+      // Convert "Not found" to empty object
+      if (result === "Not found") {
+        return {}
+      }
+      throw new Error(
+        `Invalid supplier part numbers format: Expected object but got string: "${result}"`,
+      )
+    }
+
+    // Validate that result is an object (not array, null, etc.)
+    if (!result || Array.isArray(result) || typeof result !== "object") {
+      const actualType =
+        result === null
+          ? "null"
+          : Array.isArray(result)
+            ? "array"
+            : typeof result
+      throw new Error(
+        `Invalid supplier part numbers format: Expected object but got ${actualType}`,
+      )
+    }
+
+    const supplierPartNumbers = result
 
     if (cacheEngine) {
       try {
@@ -1483,8 +1513,23 @@ export class NormalComponent<
     }
 
     this._queueAsyncEffect("get-supplier-part-numbers", async () => {
-      this._asyncSupplierPartNumbers = await supplierPartNumbersMaybePromise
-      this._markDirty("PartsEngineRender")
+      await supplierPartNumbersMaybePromise
+        .then((supplierPartNumbers) => {
+          this._asyncSupplierPartNumbers = supplierPartNumbers
+          this._markDirty("PartsEngineRender")
+        })
+        .catch((error: Error) => {
+          // Log structured error to Circuit JSON
+          this._asyncSupplierPartNumbers = {}
+          const errorObj = unknown_error_finding_part.parse({
+            type: "unknown_error_finding_part",
+            message: `Failed to fetch supplier part numbers for ${this.getString()}: ${error.message}`,
+            source_component_id: this.source_component_id,
+            subcircuit_id: this.getSubcircuit()?.subcircuit_id,
+          })
+          db.unknown_error_finding_part.insert(errorObj)
+          this._markDirty("PartsEngineRender")
+        })
     })
   }
 
diff --git a/package.json b/package.json
index ed16fde80..b7b57c287 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
     "bun-match-svg": "0.0.12",
     "calculate-elbow": "^0.0.12",
     "chokidar-cli": "^3.0.0",
-    "circuit-json": "^0.0.288",
+    "circuit-json": "^0.0.291",
     "circuit-json-to-bpc": "^0.0.13",
     "circuit-json-to-connectivity-map": "^0.0.22",
     "circuit-json-to-gltf": "^0.0.31",
diff --git a/tests/components/normal-components/parts-engine-error-handling1.test.tsx b/tests/components/normal-components/parts-engine-error-handling1.test.tsx
new file mode 100644
index 000000000..695213117
--- /dev/null
+++ b/tests/components/normal-components/parts-engine-error-handling1.test.tsx
@@ -0,0 +1,65 @@
+import { test, expect } from "bun:test"
+import { getTestFixture } from "tests/fixtures/get-test-fixture"
+
+test("parts engine handles errors gracefully and logs them to Circuit JSON", async () => {
+  // Test 1: HTML error page
+  const { circuit: circuit1 } = getTestFixture()
+  const htmlMock = {
+    findPart: async () =>
+      "<!DOCTYPE html><html><body>Internal Server Error</body></html>",
+  } as any
+
+  circuit1.add(
+    <board partsEngine={htmlMock} width="20mm" height="20mm">
+      <resistor name="R1" resistance="10k" footprint="0402" />
+    </board>,
+  )
+  await circuit1.renderUntilSettled()
+
+  const sc1 = circuit1.db.source_component.list()[0]
+  expect(sc1.supplier_part_numbers).toEqual({})
+  const errors1 = circuit1.db.unknown_error_finding_part.list()
+  expect(errors1.length).toBeGreaterThan(0)
+  expect(errors1[0].message).toContain("Failed to fetch supplier part numbers")
+  expect(errors1[0].message).toContain("<!DOCTYPE")
+
+  // Test 2: Network failure
+  const { circuit: circuit2 } = getTestFixture()
+  const networkMock = {
+    findPart: async () => {
+      throw new Error("Network request failed")
+    },
+  }
+
+  circuit2.add(
+    <board partsEngine={networkMock} width="20mm" height="20mm">
+      <resistor name="R2" resistance="10k" footprint="0402" />
+    </board>,
+  )
+  await circuit2.renderUntilSettled()
+
+  const sc2 = circuit2.db.source_component.list()[0]
+  expect(sc2.supplier_part_numbers).toEqual({})
+  const errors2 = circuit2.db.unknown_error_finding_part.list()
+  expect(errors2.length).toBeGreaterThan(0)
+  expect(errors2[0].message).toContain("Network request failed")
+
+  // Test 3: Invalid format (array instead of object)
+  const { circuit: circuit3 } = getTestFixture()
+  const invalidMock = {
+    findPart: async () => ["123-456", "789-012"],
+  } as any
+
+  circuit3.add(
+    <board partsEngine={invalidMock} width="20mm" height="20mm">
+      <resistor name="R3" resistance="10k" footprint="0402" />
+    </board>,
+  )
+  await circuit3.renderUntilSettled()
+
+  const sc3 = circuit3.db.source_component.list()[0]
+  expect(sc3.supplier_part_numbers).toEqual({})
+  const errors3 = circuit3.db.unknown_error_finding_part.list()
+  expect(errors3.length).toBeGreaterThan(0)
+  expect(errors3[0].message).toContain("Invalid supplier part numbers format")
+})
diff --git a/tests/components/normal-components/parts-engine-error-handling2.test.tsx b/tests/components/normal-components/parts-engine-error-handling2.test.tsx
new file mode 100644
index 000000000..31428ad54
--- /dev/null
+++ b/tests/components/normal-components/parts-engine-error-handling2.test.tsx
@@ -0,0 +1,46 @@
+import { test, expect } from "bun:test"
+import { getTestFixture } from "tests/fixtures/get-test-fixture"
+
+test("parts engine processes valid responses and special cases correctly", async () => {
+  // Test 1: Valid supplier part numbers
+  const { circuit: circuit1 } = getTestFixture()
+  const validMock = {
+    findPart: async () => ({
+      digikey: ["123-456"],
+      mouser: ["789-012"],
+    }),
+  }
+
+  circuit1.add(
+    <board partsEngine={validMock} width="20mm" height="20mm">
+      <resistor name="R1" resistance="10k" footprint="0402" />
+    </board>,
+  )
+  await circuit1.renderUntilSettled()
+
+  const sc1 = circuit1.db.source_component.list()[0]
+  expect(sc1.supplier_part_numbers).toEqual({
+    digikey: ["123-456"],
+    mouser: ["789-012"],
+  })
+  const errors1 = circuit1.db.unknown_error_finding_part.list()
+  expect(errors1.length).toBe(0)
+
+  // Test 2: "Not found" response (valid, converts to empty object)
+  const { circuit: circuit2 } = getTestFixture()
+  const notFoundMock = {
+    findPart: async () => "Not found",
+  } as any
+
+  circuit2.add(
+    <board partsEngine={notFoundMock} width="20mm" height="20mm">
+      <resistor name="R2" resistance="10k" footprint="0402" />
+    </board>,
+  )
+  await circuit2.renderUntilSettled()
+
+  const sc2 = circuit2.db.source_component.list()[0]
+  expect(sc2.supplier_part_numbers).toEqual({})
+  const errors2 = circuit2.db.unknown_error_finding_part.list()
+  expect(errors2.length).toBe(0)
+})