diff --git a/docs/guides/managed/managed-code-analysis.md b/docs/guides/managed/managed-code-analysis.md
index e21eba91dc..52fe21be53 100644
--- a/docs/guides/managed/managed-code-analysis.md
+++ b/docs/guides/managed/managed-code-analysis.md
@@ -650,7 +650,8 @@ unchanged signature. Comparison retains exact byte-based pairs for malformed
 signatures, including empty, truncated, or invalid headers, but reports them as
 unknown with a `signature-malformed` limitation when no change is observed.
 This applies to historical Evidence without signature-resolution attestation as
-well. Runtime-provided methods are counted separately in
+well. Runtime-provided methods have the Runtime code type or the InternalCall
+implementation flag, as core library FCalls do. They are counted separately in
 `native_implementations.runtime_provided`; they have no file-backed native body
 for this workflow to map and do not increase `native_body_unresolved`. Historical
 verification Evidence without this separate count leaves it unknown (`null`).
diff --git a/src/dotnet/ManagedMethodBodyReader.ts b/src/dotnet/ManagedMethodBodyReader.ts
index f94727751a..b51122533a 100644
--- a/src/dotnet/ManagedMethodBodyReader.ts
+++ b/src/dotnet/ManagedMethodBodyReader.ts
@@ -128,10 +128,11 @@ export const methodBody = (
   const native =
     context.implementation.codeType !== "il" ||
     context.implementation.managedKind !== "managed" ||
-    context.implementation.pinvokeFlag;
+    context.implementation.pinvokeFlag ||
+    context.implementation.internalCall;
   if (native) {
     const issue =
-      "CIL decoding is unavailable for native, runtime, unmanaged, or P/Invoke implementations";
+      "CIL decoding is unavailable for native, runtime, InternalCall, unmanaged, or P/Invoke implementations";
     return {
       body: emptyMethodBody(rva, "partial", issue),
       tokenInstructions: [],
diff --git a/src/dotnet/ManagedMethodDefinitionRows.ts b/src/dotnet/ManagedMethodDefinitionRows.ts
index 0c6c3db4d4..0563ab3fa5 100644
--- a/src/dotnet/ManagedMethodDefinitionRows.ts
+++ b/src/dotnet/ManagedMethodDefinitionRows.ts
@@ -6,6 +6,8 @@ export interface ManagedMethodImplementationFlags {
   readonly codeType: "il" | "native" | "optil" | "runtime";
   readonly managedKind: "managed" | "unmanaged";
   readonly pinvokeFlag: boolean;
+  /** MethodImplOptions.InternalCall (0x1000): the runtime implements the body. */
+  readonly internalCall: boolean;
 }
 
 const METHOD_CODE_TYPES = ["il", "native", "optil", "runtime"] as const;
@@ -42,6 +44,7 @@ export const readMethodDefinitionRow = (
       codeType: METHOD_CODE_TYPES[(implFlags & 0x0003) as 0 | 1 | 2 | 3],
       managedKind: (implFlags & 0x0004) === 0 ? "managed" : "unmanaged",
       pinvokeFlag: (flags & 0x2000) !== 0,
+      internalCall: (implFlags & 0x1000) !== 0,
     },
   };
 };
diff --git a/src/dotnet/ManagedNativeBoundaryHelpers.ts b/src/dotnet/ManagedNativeBoundaryHelpers.ts
index b38612d6d7..e88517cdc2 100644
--- a/src/dotnet/ManagedNativeBoundaryHelpers.ts
+++ b/src/dotnet/ManagedNativeBoundaryHelpers.ts
@@ -321,9 +321,15 @@ export const nativeImplementations = (
   const implementations: NativeImplementation[] = [];
   for (const method of methods) {
     if (method.kind !== "method") continue;
-    const { codeType, managedKind, pinvokeFlag } = method.implementation;
+    const { codeType, managedKind, pinvokeFlag, internalCall } =
+      method.implementation;
     const pinvokeDeclared = pinvokeTokens.has(method.token) || pinvokeFlag;
-    if (!pinvokeDeclared && codeType === "il" && managedKind === "managed")
+    if (
+      !pinvokeDeclared &&
+      !internalCall &&
+      codeType === "il" &&
+      managedKind === "managed"
+    )
       continue;
     implementations.push({
       token: method.token,
@@ -335,7 +341,12 @@ export const nativeImplementations = (
       code_type: codeType,
       managed_kind: managedKind,
       pinvoke_declared: pinvokeDeclared,
-      boundary_kind: boundaryKind(pinvokeDeclared, codeType, managedKind),
+      boundary_kind: boundaryKind(
+        pinvokeDeclared,
+        codeType,
+        managedKind,
+        internalCall,
+      ),
       body_interpretation:
         method.rva === 0 ? "not-file-backed" : "native-or-runtime",
     });
@@ -347,10 +358,11 @@ const boundaryKind = (
   pinvokeDeclared: boolean,
   codeType: ManagedMethodImplementationFlags["codeType"],
   managedKind: ManagedMethodImplementationFlags["managedKind"],
+  internalCall: boolean,
 ): NativeImplementation["boundary_kind"] => {
   if (pinvokeDeclared) return "pinvoke";
   if (codeType === "native") return "native-body";
-  if (codeType === "runtime") return "runtime-provided";
+  if (codeType === "runtime" || internalCall) return "runtime-provided";
   if (managedKind === "unmanaged") return "unmanaged-method";
   return "mixed-or-unknown";
 };
diff --git a/src/dotnet/ManagedNativeBoundaryInspector.test.ts b/src/dotnet/ManagedNativeBoundaryInspector.test.ts
index 384d0c4d6d..2e51551768 100644
--- a/src/dotnet/ManagedNativeBoundaryInspector.test.ts
+++ b/src/dotnet/ManagedNativeBoundaryInspector.test.ts
@@ -524,6 +524,40 @@ it.each([
   },
 );
 
+it.each([
+  { zeroRva: true, status: "absent", interpretation: "not-file-backed" },
+  { zeroRva: false, status: "partial", interpretation: "native-or-runtime" },
+])(
+  "publishes an InternalCall method as a runtime-provided boundary consistently with body admission (zero RVA: $zeroRva)",
+  ({ zeroRva, status, interpretation }) => {
+    // MethodImplOptions.InternalCall: the runtime implements the body. Core
+    // library FCalls carry this bit with IL code type and no RVA. A malformed
+    // row can keep IL flags and a file-backed RVA, which the runtime rejects.
+    const { members, boundaries } = inspectImplementationFixture({
+      implFlags: 0x1000,
+      zeroRva,
+    });
+    expect(boundaries.native_implementations).toMatchObject([
+      {
+        token: members.methods[0]?.token,
+        impl_flags: 0x1000,
+        code_type: "il",
+        managed_kind: "managed",
+        pinvoke_declared: false,
+        boundary_kind: "runtime-provided",
+        body_interpretation: interpretation,
+      },
+    ]);
+    expect(boundaries.summary.native_implementation_count).toBe(1);
+    expect(members.methods[0]?.body).toMatchObject({
+      status,
+      il_sha256: null,
+    });
+    if (!zeroRva) expect(members.methods[0]?.body.issue).toMatch(/CIL/u);
+    else expect(members.methods[0]?.body.issue).toBeNull();
+  },
+);
+
 it.each([
   {
     name: "PInvoke flag on managed IL",