diff --git a/experiments/atomic-codemode/native-contract.mjs b/experiments/atomic-codemode/native-contract.mjs
index f8da20fce..3bb44c9c1 100644
--- a/experiments/atomic-codemode/native-contract.mjs
+++ b/experiments/atomic-codemode/native-contract.mjs
@@ -79,6 +79,10 @@ export const readNativeFacet = (fn, name, label, parse) => {
         fn[name] === undefined,
         `Native ${label} is both present and unavailable`,
       );
+      requireFact(
+        typeof reason === "string",
+        `Native ${label} failure reason must be text`,
+      );
       return err(
         new FactFailure(
           "capability_unavailable",
diff --git a/experiments/atomic-codemode/native-facet-failures.test.mjs b/experiments/atomic-codemode/native-facet-failures.test.mjs
new file mode 100644
index 000000000..bb52e0b2a
--- /dev/null
+++ b/experiments/atomic-codemode/native-facet-failures.test.mjs
@@ -0,0 +1,77 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { parseNativeIR } from "./native-ir.mjs";
+import { readNativeGraphEvidence } from "./native-ir-contract.mjs";
+
+// Minimal valid graph: this regression concerns facet admission, not SSA rules.
+const document = () => ({
+  binary: "/fixture",
+  count: 1,
+  language: "c",
+  error: null,
+  functions: [
+    {
+      address_hex: "0x1000",
+      error: null,
+      code: "reconstructed C",
+      atomic_facts: {
+        schema_version: 3,
+        blocks: [
+          {
+            id: 0,
+            start: "0x1000",
+            operations: [],
+            predecessors: [],
+            successors: [],
+          },
+        ],
+        operations: [],
+        values: [],
+        coverage: {
+          scope: "retained native graph",
+          machine_semantic_equivalence: "unknown",
+          indirect_branch_operations: [],
+          omitted_definition_ids: [],
+          issues: [],
+        },
+      },
+    },
+  ],
+});
+
+test("malformed facet failure values stay local and preserve healthy graph/code/source views", () => {
+  for (const name of [
+    "atomic_facts",
+    "atomic_calls",
+    "atomic_parameters",
+    "atomic_switches",
+    "atomic_projection",
+  ])
+    for (const reason of [null, 7, false, {}, []]) {
+      const doc = document();
+      if (name === "atomic_facts") delete doc.functions[0].atomic_facts;
+      doc.functions[0][`${name}_error`] = reason;
+      const text = JSON.stringify(doc),
+        model = parseNativeIR(text, "0x1000");
+      assert.equal(model.code, "reconstructed C");
+      if (name !== "atomic_facts") {
+        assert.equal(model.facets.recovered_ir.availability, "available");
+        assert.equal(model.blocks({}).total, 1);
+        assert.ok(readNativeGraphEvidence(text).text.length);
+      } else {
+        assert.equal(
+          model.facets.recovered_ir.error.code,
+          "invalid_provider_output",
+        );
+        assert.throws(
+          () => readNativeGraphEvidence(text),
+          (e) => e.code === "invalid_provider_output",
+        );
+      }
+      if (name === "atomic_parameters")
+        assert.equal(
+          model.facets.parameters.error.code,
+          "invalid_provider_output",
+        );
+    }
+});
diff --git a/experiments/atomic-codemode/native-ir-contract.mjs b/experiments/atomic-codemode/native-ir-contract.mjs
index ce0a4dc31..189d5ecee 100644
--- a/experiments/atomic-codemode/native-ir-contract.mjs
+++ b/experiments/atomic-codemode/native-ir-contract.mjs
@@ -69,15 +69,15 @@ const documentSchema = z.object({
         code: z.string(),
         error: z.null(),
         atomic_facts: z.unknown().optional(),
-        atomic_facts_error: z.string().optional(),
+        atomic_facts_error: z.unknown().optional(),
         atomic_calls: z.unknown().optional(),
-        atomic_calls_error: z.string().optional(),
+        atomic_calls_error: z.unknown().optional(),
         atomic_parameters: z.unknown().optional(),
-        atomic_parameters_error: z.string().optional(),
+        atomic_parameters_error: z.unknown().optional(),
         atomic_switches: z.unknown().optional(),
-        atomic_switches_error: z.string().optional(),
+        atomic_switches_error: z.unknown().optional(),
         atomic_projection: z.unknown().optional(),
-        atomic_projection_error: z.string().optional(),
+        atomic_projection_error: z.unknown().optional(),
       }),
     )
     .length(1),
@@ -241,12 +241,15 @@ export function readNativeGraphEvidence(text) {
         "This retained source is not a native function record",
       );
     const { fn } = readFunction(raw);
-    if (fn.atomic_facts === undefined)
-      throw new FactFailure(
-        "capability_unavailable",
-        "Recovered graph source was not captured",
-        { native_error: fn.atomic_facts_error?.slice(0, 1024) },
+    if (fn.atomic_facts === undefined) {
+      const graph = readNativeFacet(
+        fn,
+        "atomic_facts",
+        "recovered IR",
+        (raw) => raw,
       );
+      if (!graph.ok) throw graph.error;
+    }
     const decoded = decodeGraphArchive(fn.atomic_facts);
     const view = decoded ?? JSON.stringify(fn.atomic_facts);
     requireFact(
diff --git a/experiments/atomic-codemode/native-parameters.test.mjs b/experiments/atomic-codemode/native-parameters.test.mjs
index 7a0f84b68..456b85f73 100644
--- a/experiments/atomic-codemode/native-parameters.test.mjs
+++ b/experiments/atomic-codemode/native-parameters.test.mjs
@@ -128,7 +128,7 @@ test("unknown type/storage is distinct from native void, malformed identities ca
 test("prototype facet works without graph/calls; unavailable/invalid prototype retains code and reason", () => {
   const available = model({
     atomic_parameters: fixture(),
-    atomic_facts_error: "capacity",
+    atomic_facts_error: { malformed: "not a failure string" },
     atomic_calls_error: "capacity",
   });
   assert.equal(available.facets.parameters.availability, "available");