diff --git a/sdk/go/openshell/v1/internal/converter/policy.go b/sdk/go/openshell/v1/internal/converter/policy.go
index 1fcb4bd9d..13b3bc7f9 100644
--- a/sdk/go/openshell/v1/internal/converter/policy.go
+++ b/sdk/go/openshell/v1/internal/converter/policy.go
@@ -245,7 +245,7 @@ func publicNetworkEndpointFromInternalProto(endpoint *sbv1.NetworkEndpoint) *pol
 		SigningRegion:                endpoint.GetSigningRegion(),
 	}
 	if ports := endpoint.GetPorts(); len(ports) > 0 {
-		result.Ports = append([]uint32(nil), ports...)
+		result.Ports = stableUnique(ports)
 	} else if port := endpoint.GetPort(); port != 0 {
 		// Older internal records may still use the legacy scalar port. The
 		// authored contract has only the canonical list representation.
@@ -435,7 +435,7 @@ func publicMatcherMapFromInternalProto(matchers map[string]*sbv1.L7QueryMatcher)
 func publicMatcherFromInternalProto(matcher *sbv1.L7QueryMatcher) *policyv1.Matcher {
 	if matcher != nil && len(matcher.GetAny()) > 0 {
 		return &policyv1.Matcher{Kind: &policyv1.Matcher_Any{Any: &policyv1.AnyMatcher{
-			Values: CopyStringSlice(matcher.GetAny()),
+			Values: stableUnique(matcher.GetAny()),
 		}}}
 	}
 	glob := ""
@@ -445,6 +445,22 @@ func publicMatcherFromInternalProto(matcher *sbv1.L7QueryMatcher) *policyv1.Matc
 	return &policyv1.Matcher{Kind: &policyv1.Matcher_Glob{Glob: glob}}
 }
 
+// stableUnique canonicalizes legacy runtime lists for public fields whose
+// protobuf contract requires unique values. Retaining the first occurrence
+// keeps the projection deterministic without changing caller-visible order.
+func stableUnique[T comparable](values []T) []T {
+	result := make([]T, 0, len(values))
+	seen := make(map[T]struct{}, len(values))
+	for _, value := range values {
+		if _, found := seen[value]; found {
+			continue
+		}
+		seen[value] = struct{}{}
+		result = append(result, value)
+	}
+	return result
+}
+
 func publicTLSMode(mode sbv1.NetworkTlsMode) string {
 	// Numeric cases keep the explicit projection compatible with deprecated
 	// internal enum values without making new SDK code depend on their names.
diff --git a/sdk/go/openshell/v1/internal/converter/policy_test.go b/sdk/go/openshell/v1/internal/converter/policy_test.go
index 351e26be0..5cd564276 100644
--- a/sdk/go/openshell/v1/internal/converter/policy_test.go
+++ b/sdk/go/openshell/v1/internal/converter/policy_test.go
@@ -393,6 +393,39 @@ func TestPolicyDocumentFromInternalProtoExplicitProjection(t *testing.T) {
 	assert.Equal(t, []string{"2025-11-25"}, policy.NetworkPolicies["api"].Endpoints[0].Mcp.Versions)
 }
 
+func TestPolicyDocumentFromInternalProtoDeduplicatesLegacyValues(t *testing.T) {
+	internal := &sbv1.SandboxPolicy{
+		Version: 1,
+		NetworkPolicies: map[string]*sbv1.NetworkPolicyRule{
+			"api": {
+				Endpoints: []*sbv1.NetworkEndpoint{{
+					Host:     "api.example.com",
+					Ports:    []uint32{443, 8443, 443},
+					Protocol: "http",
+					Rules: []*sbv1.L7Rule{{Allow: &sbv1.L7Allow{
+						Method: "GET",
+						Query: map[string]*sbv1.L7QueryMatcher{
+							"state": {Any: []string{"open", "closed", "open"}},
+						},
+					}}},
+				}},
+			},
+		},
+	}
+
+	policy := PolicyDocumentFromInternalProto(internal)
+	require.NotNil(t, policy)
+	endpoint := policy.NetworkPolicies["api"].Endpoints[0]
+	assert.Equal(t, []uint32{443, 8443}, endpoint.Ports)
+	require.NotNil(t, endpoint.Rules[0].Allow)
+	assert.Equal(t, []string{"open", "closed"}, endpoint.Rules[0].Allow.Query["state"].Any)
+
+	// Policy updates use the checked conversion path, so a projected policy
+	// must satisfy the public protobuf uniqueness constraints before submission.
+	_, err := PolicyDocumentToProtoChecked(policy)
+	require.NoError(t, err)
+}
+
 func TestSandboxPolicyRoundTrip(t *testing.T) {
 	original := &v1.PolicyDocument{
 		Version: 5,
diff --git a/sdk/typescript/src/client.test.ts b/sdk/typescript/src/client.test.ts
index 804e54c79..aad4108cb 100644
--- a/sdk/typescript/src/client.test.ts
+++ b/sdk/typescript/src/client.test.ts
@@ -1317,6 +1317,56 @@ describe('config / policy', () => {
     expect(Object.hasOwn(Object, 'children')).toBe(false);
   });
 
+  it('getConfig canonicalizes legacy lists before a checked policy update', async () => {
+    let submittedPolicy: unknown;
+    const sandbox = client({
+      getSandbox: () => readySandbox('sb', 'sb-id'),
+      getSandboxConfig: () => ({
+        policy: {
+          version: 1,
+          networkPolicies: {
+            api: {
+              endpoints: [
+                {
+                  host: 'api.example.com',
+                  ports: [443, 8443, 443],
+                  protocol: 'http',
+                  rules: [
+                    {
+                      allow: {
+                        method: 'GET',
+                        query: { state: { any: ['open', 'closed', 'open'] } },
+                      },
+                    },
+                  ],
+                },
+              ],
+            },
+          },
+        },
+        settings: {},
+      }),
+      updateConfig: (req) => {
+        submittedPolicy = req.policy;
+        return { version: 2, policyHash: 'canonical', settingsRevision: 0n, deleted: false };
+      },
+    });
+
+    const config = await sandbox.getConfig('sb');
+    const projectedPolicy = config.policy;
+    expect(projectedPolicy).toBeDefined();
+    if (!projectedPolicy) throw new Error('expected projected policy');
+    const endpoint = projectedPolicy.networkPolicies.api?.endpoints[0];
+    expect(endpoint?.ports).toEqual([443, 8443]);
+    expect(endpoint?.rules[0]?.allow?.query.state?.kind).toEqual({
+      case: 'any',
+      value: expect.objectContaining({ values: ['open', 'closed'] }),
+    });
+
+    await expect(sandbox.setPolicy('sb', projectedPolicy)).resolves.toMatchObject({ policyHash: 'canonical' });
+    expect(submittedPolicy).toBeDefined();
+  });
+
   it('setPolicy sends global=false + version pin and (wait) polls until the hash matches', async () => {
     let updateReq: {
       sandbox?: string;
diff --git a/sdk/typescript/src/client.ts b/sdk/typescript/src/client.ts
index 72083d970..1033f2b21 100644
--- a/sdk/typescript/src/client.ts
+++ b/sdk/typescript/src/client.ts
@@ -606,7 +606,7 @@ function policyEndpointFromRuntime(
   const mcpProtocol = endpoint.protocol.toLowerCase() === 'mcp';
   return {
     host: endpoint.host,
-    ports: endpoint.ports.length > 0 ? [...endpoint.ports] : endpoint.port === 0 ? [] : [endpoint.port],
+    ports: endpoint.ports.length > 0 ? stableUnique(endpoint.ports) : endpoint.port === 0 ? [] : [endpoint.port],
     protocol: endpoint.protocol,
     tls: runtimeTLSMode(endpoint.tls),
     enforcement: runtimeEnforcementMode(endpoint.enforcement),
@@ -703,11 +703,17 @@ function policyMCPMethod(
 
 function policyMatcherFromRuntime(matcher: RuntimeMatcher | undefined): MatcherInit {
   if (matcher && matcher.any.length > 0) {
-    return { kind: { case: 'any', value: { values: [...matcher.any] } } };
+    return { kind: { case: 'any', value: { values: stableUnique(matcher.any) } } };
   }
   return { kind: { case: 'glob', value: matcher?.glob ?? '' } };
 }
 
+// The public protobuf contract requires these projected lists to be unique.
+// Set iteration retains the first-seen order from legacy runtime records.
+function stableUnique<T>(values: readonly T[]): T[] {
+  return [...new Set(values)];
+}
+
 function policyMatcherMapFromRuntime(matchers: Record<string, RuntimeMatcher>): Record<string, MatcherInit> {
   return Object.fromEntries(
     Object.entries(matchers).map(([name, matcher]) => [name, policyMatcherFromRuntime(matcher)]),