diff --git a/Makefile b/Makefile
index e33741ef220..44669fa1bfe 100644
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,7 @@ sync:
 	git fetch --all
 
 generate-protocol-tests:
+	rm -rf ./smithy-typescript-protocol-test-codegen/build/smithyprojections/smithy-typescript-protocol-test-codegen
 	./gradlew :smithy-typescript-protocol-test-codegen:build
 	rm -rf ./private/smithy-rpcv2-cbor
 	rm -rf ./private/smithy-rpcv2-cbor-schema
diff --git a/private/my-local-model-schema/src/commands/GetNumbersCommand.ts b/private/my-local-model-schema/src/commands/GetNumbersCommand.ts
index ea46d633848..664828875cd 100644
--- a/private/my-local-model-schema/src/commands/GetNumbersCommand.ts
+++ b/private/my-local-model-schema/src/commands/GetNumbersCommand.ts
@@ -68,6 +68,8 @@ export interface GetNumbersCommandOutput extends GetNumbersResponse, __MetadataB
  *
  * @throws {@link XYZServiceServiceException} (client fault)
  *
+ * @throws {@link MainServiceLinkedError} (client fault)
+ *
  * @throws {@link XYZServiceSyntheticServiceException}
  * <p>Base exception class for all service exceptions from XYZService service.</p>
  *
diff --git a/private/my-local-model-schema/src/commands/TradeEventStreamCommand.ts b/private/my-local-model-schema/src/commands/TradeEventStreamCommand.ts
index a86781205af..7fd413320cb 100644
--- a/private/my-local-model-schema/src/commands/TradeEventStreamCommand.ts
+++ b/private/my-local-model-schema/src/commands/TradeEventStreamCommand.ts
@@ -68,6 +68,8 @@ export interface TradeEventStreamCommandOutput extends TradeEventStreamResponse,
  * @see {@link TradeEventStreamCommandOutput} for command's `response` shape.
  * @see {@link XYZServiceClientResolvedConfig | config} for XYZServiceClient's `config` shape.
  *
+ * @throws {@link MainServiceLinkedError} (client fault)
+ *
  * @throws {@link XYZServiceSyntheticServiceException}
  * <p>Base exception class for all service exceptions from XYZService service.</p>
  *
diff --git a/private/my-local-model-schema/src/models/errors.ts b/private/my-local-model-schema/src/models/errors.ts
index 6ae3754be39..146c7f7243d 100644
--- a/private/my-local-model-schema/src/models/errors.ts
+++ b/private/my-local-model-schema/src/models/errors.ts
@@ -44,6 +44,25 @@ export class HaltError extends __BaseException {
   }
 }
 
+/**
+ * @public
+ */
+export class MainServiceLinkedError extends __BaseException {
+  readonly name = "MainServiceLinkedError" as const;
+  readonly $fault = "client" as const;
+  /**
+   * @internal
+   */
+  constructor(opts: __ExceptionOptionType<MainServiceLinkedError, __BaseException>) {
+    super({
+      name: "MainServiceLinkedError",
+      $fault: "client",
+      ...opts,
+    });
+    Object.setPrototypeOf(this, MainServiceLinkedError.prototype);
+  }
+}
+
 /**
  * @public
  */
diff --git a/private/my-local-model-schema/src/schemas/schemas_0.ts b/private/my-local-model-schema/src/schemas/schemas_0.ts
index dd693af8d15..8991f413638 100644
--- a/private/my-local-model-schema/src/schemas/schemas_0.ts
+++ b/private/my-local-model-schema/src/schemas/schemas_0.ts
@@ -4,6 +4,7 @@ const _GN = "GetNumbers";
 const _GNR = "GetNumbersRequest";
 const _GNRe = "GetNumbersResponse";
 const _HE = "HaltError";
+const _MSLE = "MainServiceLinkedError";
 const _MTE = "MysteryThrottlingError";
 const _RE = "RetryableError";
 const _TE = "TradeEvents";
@@ -35,6 +36,7 @@ import type { StaticErrorSchema, StaticOperationSchema, StaticStructureSchema }
 import {
   CodedThrottlingError as __CodedThrottlingError,
   HaltError as __HaltError,
+  MainServiceLinkedError as __MainServiceLinkedError,
   MysteryThrottlingError as __MysteryThrottlingError,
   RetryableError as __RetryableError,
   XYZServiceServiceException as __XYZServiceServiceException,
@@ -71,6 +73,12 @@ export var HaltError: StaticErrorSchema = [-3, n0, _HE,
   []
 ];
 TypeRegistry.for(n0).registerError(HaltError, __HaltError);
+export var MainServiceLinkedError: StaticErrorSchema = [-3, n0, _MSLE,
+  { [_e]: _c, [_hE]: 400 },
+  [],
+  []
+];
+TypeRegistry.for(n0).registerError(MainServiceLinkedError, __MainServiceLinkedError);
 export var MysteryThrottlingError: StaticErrorSchema = [-3, n0, _MTE,
   { [_e]: _c },
   [],
diff --git a/private/my-local-model-schema/test/index-objects.spec.mjs b/private/my-local-model-schema/test/index-objects.spec.mjs
index e0dc28e52e4..07ab38eb471 100644
--- a/private/my-local-model-schema/test/index-objects.spec.mjs
+++ b/private/my-local-model-schema/test/index-objects.spec.mjs
@@ -2,6 +2,7 @@ import {
   CodedThrottlingError,
   GetNumbersCommand,
   HaltError,
+  MainServiceLinkedError,
   MysteryThrottlingError,
   RetryableError,
   TradeEventStreamCommand,
@@ -20,6 +21,7 @@ assert(typeof TradeEventStreamCommand === "function");
 // errors
 assert(CodedThrottlingError.prototype instanceof XYZServiceSyntheticServiceException);
 assert(HaltError.prototype instanceof XYZServiceSyntheticServiceException);
+assert(MainServiceLinkedError.prototype instanceof XYZServiceSyntheticServiceException);
 assert(MysteryThrottlingError.prototype instanceof XYZServiceSyntheticServiceException);
 assert(RetryableError.prototype instanceof XYZServiceSyntheticServiceException);
 assert(XYZServiceServiceException.prototype instanceof XYZServiceSyntheticServiceException);
diff --git a/private/my-local-model-schema/test/index-types.ts b/private/my-local-model-schema/test/index-types.ts
index 1c4ee56ab81..fb0196a7dcd 100644
--- a/private/my-local-model-schema/test/index-types.ts
+++ b/private/my-local-model-schema/test/index-types.ts
@@ -16,6 +16,7 @@ export type {
   TradeEventStreamResponse,
   CodedThrottlingError,
   HaltError,
+  MainServiceLinkedError,
   MysteryThrottlingError,
   RetryableError,
   XYZServiceServiceException,
diff --git a/private/my-local-model/src/commands/GetNumbersCommand.ts b/private/my-local-model/src/commands/GetNumbersCommand.ts
index 7a71ff923ee..890256a61f2 100644
--- a/private/my-local-model/src/commands/GetNumbersCommand.ts
+++ b/private/my-local-model/src/commands/GetNumbersCommand.ts
@@ -69,6 +69,8 @@ export interface GetNumbersCommandOutput extends GetNumbersResponse, __MetadataB
  *
  * @throws {@link XYZServiceServiceException} (client fault)
  *
+ * @throws {@link MainServiceLinkedError} (client fault)
+ *
  * @throws {@link XYZServiceSyntheticServiceException}
  * <p>Base exception class for all service exceptions from XYZService service.</p>
  *
diff --git a/private/my-local-model/src/commands/TradeEventStreamCommand.ts b/private/my-local-model/src/commands/TradeEventStreamCommand.ts
index 7604b4959ae..c1d258edc37 100644
--- a/private/my-local-model/src/commands/TradeEventStreamCommand.ts
+++ b/private/my-local-model/src/commands/TradeEventStreamCommand.ts
@@ -74,6 +74,8 @@ export interface TradeEventStreamCommandOutput extends TradeEventStreamResponse,
  * @see {@link TradeEventStreamCommandOutput} for command's `response` shape.
  * @see {@link XYZServiceClientResolvedConfig | config} for XYZServiceClient's `config` shape.
  *
+ * @throws {@link MainServiceLinkedError} (client fault)
+ *
  * @throws {@link XYZServiceSyntheticServiceException}
  * <p>Base exception class for all service exceptions from XYZService service.</p>
  *
diff --git a/private/my-local-model/src/models/errors.ts b/private/my-local-model/src/models/errors.ts
index 6ae3754be39..146c7f7243d 100644
--- a/private/my-local-model/src/models/errors.ts
+++ b/private/my-local-model/src/models/errors.ts
@@ -44,6 +44,25 @@ export class HaltError extends __BaseException {
   }
 }
 
+/**
+ * @public
+ */
+export class MainServiceLinkedError extends __BaseException {
+  readonly name = "MainServiceLinkedError" as const;
+  readonly $fault = "client" as const;
+  /**
+   * @internal
+   */
+  constructor(opts: __ExceptionOptionType<MainServiceLinkedError, __BaseException>) {
+    super({
+      name: "MainServiceLinkedError",
+      $fault: "client",
+      ...opts,
+    });
+    Object.setPrototypeOf(this, MainServiceLinkedError.prototype);
+  }
+}
+
 /**
  * @public
  */
diff --git a/private/my-local-model/src/protocols/Rpcv2cbor.ts b/private/my-local-model/src/protocols/Rpcv2cbor.ts
index d053e51c15e..7d04ffe29a6 100644
--- a/private/my-local-model/src/protocols/Rpcv2cbor.ts
+++ b/private/my-local-model/src/protocols/Rpcv2cbor.ts
@@ -35,6 +35,7 @@ import { TradeEventStreamCommandInput, TradeEventStreamCommandOutput } from "../
 import {
   CodedThrottlingError,
   HaltError,
+  MainServiceLinkedError,
   MysteryThrottlingError,
   RetryableError,
   XYZServiceServiceException,
@@ -133,6 +134,9 @@ const de_CommandError = async (
     case "HaltError":
     case "org.xyz.v1#HaltError":
       throw await de_HaltErrorRes(parsedOutput, context);
+    case "MainServiceLinkedError":
+    case "org.xyz.v1#MainServiceLinkedError":
+      throw await de_MainServiceLinkedErrorRes(parsedOutput, context);
     case "MysteryThrottlingError":
     case "org.xyz.v1#MysteryThrottlingError":
       throw await de_MysteryThrottlingErrorRes(parsedOutput, context);
@@ -184,6 +188,22 @@ const de_HaltErrorRes = async (
   return __decorateServiceException(exception, body);
 };
 
+/**
+ * deserializeRpcv2cborMainServiceLinkedErrorRes
+ */
+const de_MainServiceLinkedErrorRes = async (
+  parsedOutput: any,
+  context: __SerdeContext
+): Promise<MainServiceLinkedError> => {
+  const body = parsedOutput.body
+  const deserialized: any = _json(body);
+  const exception = new MainServiceLinkedError({
+    $metadata: deserializeMetadata(parsedOutput),
+    ...deserialized
+  });
+  return __decorateServiceException(exception, body);
+};
+
 /**
  * deserializeRpcv2cborMysteryThrottlingErrorRes
  */
@@ -382,6 +402,8 @@ const se_Alpha_event = (
 
     // de_HaltError omitted.
 
+    // de_MainServiceLinkedError omitted.
+
     // de_MysteryThrottlingError omitted.
 
     // de_RetryableError omitted.
diff --git a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/knowledge/ServiceClosure.java b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/knowledge/ServiceClosure.java
index 26339de4fa8..9e0017cc0de 100644
--- a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/knowledge/ServiceClosure.java
+++ b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/knowledge/ServiceClosure.java
@@ -106,6 +106,7 @@ private ServiceClosure(
         Set<OperationShape> containedOperations = topDown.getContainedOperations(service);
         operations.addAll(containedOperations);
         scan(containedOperations);
+        scan(service);
         scanned.clear();
         deconflictSchemaVarNames();
     }
@@ -271,6 +272,13 @@ private void scan(Collection<Shape> shapes) {
                     operations.add(operation);
                     existsAsSchema.add(operation);
                 }
+                case SERVICE -> {
+                    ServiceShape serviceShape = (ServiceShape) shape;
+                    serviceShape.getErrorsSet().forEach(errorShapeId -> {
+                        Shape errorShape = model.expectShape(errorShapeId);
+                        scan(errorShape);
+                    });
+                }
                 case BYTE, INT_ENUM, SHORT, INTEGER, LONG, FLOAT, DOUBLE, BIG_INTEGER, BIG_DECIMAL, BOOLEAN, STRING,
                      TIMESTAMP, DOCUMENT, ENUM, BLOB -> {
                     if (shape.isEnumShape() || shape.isIntEnumShape() || shape.hasTrait(EnumTrait.class)) {
diff --git a/smithy-typescript-protocol-test-codegen/model/my-local-model/main.smithy b/smithy-typescript-protocol-test-codegen/model/my-local-model/main.smithy
index c03a53a517e..9eb591a0f1c 100644
--- a/smithy-typescript-protocol-test-codegen/model/my-local-model/main.smithy
+++ b/smithy-typescript-protocol-test-codegen/model/my-local-model/main.smithy
@@ -12,8 +12,15 @@ service XYZService {
         GetNumbers
         TradeEventStream
     ]
+    errors: [
+        MainServiceLinkedError
+    ]
 }
 
+@error("client")
+@httpError(400)
+structure MainServiceLinkedError {}
+
 @readonly
 operation GetNumbers {
     input: GetNumbersRequest
@@ -91,3 +98,35 @@ structure Alpha {
     id: String
     timestamp: Timestamp
 }
+
+@rpcv2Cbor
+@documentation("a second service in the same model, unused.")
+service UnusedService {
+    version: "1.0"
+    operations: [
+        UnusedOperation
+    ]
+    errors: [
+        UnusedServiceLinkedError
+    ]
+}
+
+operation UnusedOperation {
+    input: Unit
+    output: Unit
+    errors: [
+        UnusedServiceOperationLinkedError
+    ]
+}
+
+@error("client")
+@httpError(400)
+structure UnusedServiceOperationLinkedError {}
+
+@error("client")
+@httpError(400)
+structure UnusedServiceLinkedError {}
+
+@error("client")
+@httpError(400)
+structure CompletelyUnlinkedError {}
diff --git a/smithy-typescript-protocol-test-codegen/model/my-local-model/secondary.smithy b/smithy-typescript-protocol-test-codegen/model/my-local-model/secondary.smithy
new file mode 100644
index 00000000000..a57446a8e3f
--- /dev/null
+++ b/smithy-typescript-protocol-test-codegen/model/my-local-model/secondary.smithy
@@ -0,0 +1,37 @@
+$version: "2.0"
+
+namespace org.xyz.secondary
+
+use smithy.protocols#rpcv2Cbor
+
+@rpcv2Cbor
+@documentation("a second service in the same model, unused.")
+service TertiaryService {
+    version: "1.0"
+    operations: [
+        TertiaryUnusedOperation
+    ]
+    errors: [
+        TertiaryUnusedServiceLinkedError
+    ]
+}
+
+operation TertiaryUnusedOperation {
+    input: Unit
+    output: Unit
+    errors: [
+        TertiaryUnusedServiceOperationLinkedError
+    ]
+}
+
+@error("client")
+@httpError(400)
+structure TertiaryUnusedServiceOperationLinkedError {}
+
+@error("client")
+@httpError(400)
+structure TertiaryUnusedServiceLinkedError {}
+
+@error("client")
+@httpError(400)
+structure TertiaryCompletelyUnlinkedError {}
diff --git a/smithy-typescript-protocol-test-codegen/smithy-build.json b/smithy-typescript-protocol-test-codegen/smithy-build.json
index 7d93617be71..629f69f5ff0 100644
--- a/smithy-typescript-protocol-test-codegen/smithy-build.json
+++ b/smithy-typescript-protocol-test-codegen/smithy-build.json
@@ -62,7 +62,7 @@
         {
           "name": "includeServices",
           "args": {
-            "services": ["org.xyz.v1#XYZService"]
+            "services": ["org.xyz.v1#XYZService", "org.xyz.v1#UnusedService", "org.xyz.secondary#TertiaryService"]
           }
         }
       ],
@@ -83,7 +83,7 @@
         {
           "name": "includeServices",
           "args": {
-            "services": ["org.xyz.v1#XYZService"]
+            "services": ["org.xyz.v1#XYZService", "org.xyz.v1#UnusedService", "org.xyz.secondary#TertiaryService"]
           }
         }
       ],