diff --git a/specification/app/Microsoft.App.DynamicSessions/main.tsp b/specification/app/Microsoft.App.DynamicSessions/main.tsp
index 902c778e2411..e8a14224c32e 100644
--- a/specification/app/Microsoft.App.DynamicSessions/main.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/main.tsp
@@ -4,7 +4,6 @@ import "@azure-tools/typespec-azure-core";
 import "./routes.tsp";
 
 using TypeSpec.Http;
-using TypeSpec.Rest;
 using TypeSpec.Versioning;
 using Azure.Core;
 
diff --git a/specification/app/Microsoft.App.DynamicSessions/models/code-execution-file.tsp b/specification/app/Microsoft.App.DynamicSessions/models/code-execution-file.tsp
index b6bdbec67d14..5011438a0a9c 100644
--- a/specification/app/Microsoft.App.DynamicSessions/models/code-execution-file.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/models/code-execution-file.tsp
@@ -1,5 +1,4 @@
 import "./common.tsp";
-using TypeSpec.Http;
 using TypeSpec.Rest;
 
 namespace Microsoft.App.DynamicSessions;
diff --git a/specification/app/Microsoft.App.DynamicSessions/models/code-execution.tsp b/specification/app/Microsoft.App.DynamicSessions/models/code-execution.tsp
index 159b998edbd5..af3ecd2d0d55 100644
--- a/specification/app/Microsoft.App.DynamicSessions/models/code-execution.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/models/code-execution.tsp
@@ -1,6 +1,5 @@
 import "./common.tsp";
 using Azure.Core;
-using TypeSpec.Http;
 using TypeSpec.Rest;
 
 namespace Microsoft.App.DynamicSessions;
@@ -17,7 +16,7 @@ model SessionCodeExecutionRequest {
   code: string;
 
   @doc("Code execution timeout in seconds.")
-  timeoutInSeconds: int64;
+  timeoutInSeconds: int32;
 }
 
 @doc("The result of the code execution.")
diff --git a/specification/app/Microsoft.App.DynamicSessions/models/common.tsp b/specification/app/Microsoft.App.DynamicSessions/models/common.tsp
index 4ac4342e7f6f..389a0a46fe0b 100644
--- a/specification/app/Microsoft.App.DynamicSessions/models/common.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/models/common.tsp
@@ -1,11 +1,8 @@
 import "@azure-tools/typespec-azure-resource-manager";
 
-using Azure.Core;
 using TypeSpec.Http;
-using TypeSpec.Rest;
 
 namespace Microsoft.App.DynamicSessions;
-using OpenAPI;
 
 @doc("The optional execution id header.")
 model ExecutionOperationIdHeader {
@@ -20,7 +17,7 @@ model SessionIdentifier {
   @query
   @minLength(1)
   @maxLength(256)
-  @pattern("^[A-Za-z0-9-_]{1,256}$")
+  @pattern("^[a-zA-Z0-9_|}{\\[\\]\\:\"\";'<>?\\/.,@#$%\\^&*()_\\-+=!~`]{4,128}$")
   identifier: string;
 }
 
diff --git a/specification/app/Microsoft.App.DynamicSessions/models/session.tsp b/specification/app/Microsoft.App.DynamicSessions/models/session.tsp
index 89b57dc147c6..1ea2a1bb8329 100644
--- a/specification/app/Microsoft.App.DynamicSessions/models/session.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/models/session.tsp
@@ -1,7 +1,5 @@
 import "./common.tsp";
 using Azure.Core;
-using TypeSpec.Http;
-using TypeSpec.Rest;
 using TypeSpec.Versioning;
 
 namespace Microsoft.App.DynamicSessions;
diff --git a/specification/app/Microsoft.App.DynamicSessions/models/sessionpool-metadata.tsp b/specification/app/Microsoft.App.DynamicSessions/models/sessionpool-metadata.tsp
index af5dae061107..6989ce9b1983 100644
--- a/specification/app/Microsoft.App.DynamicSessions/models/sessionpool-metadata.tsp
+++ b/specification/app/Microsoft.App.DynamicSessions/models/sessionpool-metadata.tsp
@@ -1,7 +1,4 @@
 import "./common.tsp";
-using Azure.Core;
-using TypeSpec.Http;
-using TypeSpec.Rest;
 using TypeSpec.Versioning;
 
 namespace Microsoft.App.DynamicSessions;
diff --git a/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2024-10-02-preview/DynamicSessions.json b/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2024-10-02-preview/DynamicSessions.json
index b4db1f21f3d5..b3c59f700608 100644
--- a/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2024-10-02-preview/DynamicSessions.json
+++ b/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2024-10-02-preview/DynamicSessions.json
@@ -634,7 +634,7 @@
         },
         "timeoutInSeconds": {
           "type": "integer",
-          "format": "int64",
+          "format": "int32",
           "description": "Code execution timeout in seconds."
         }
       },
@@ -800,7 +800,7 @@
       "type": "string",
       "minLength": 1,
       "maxLength": 256,
-      "pattern": "^[A-Za-z0-9-_]{1,256}$",
+      "pattern": "^[a-zA-Z0-9_|}{\\[\\]\\:\"\";'<>?\\/.,@#$%\\^&*()_\\-+=!~`]{4,128}$",
       "x-ms-parameter-location": "method"
     },
     "SessionResourceFilePathQueryParameter": {
diff --git a/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2025-02-02-preview/DynamicSessions.json b/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2025-02-02-preview/DynamicSessions.json
index 8316882ab3f0..ecf8f0af1df1 100644
--- a/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2025-02-02-preview/DynamicSessions.json
+++ b/specification/app/data-plane/Microsoft.App.DynamicSessions/preview/2025-02-02-preview/DynamicSessions.json
@@ -892,7 +892,7 @@
         },
         "timeoutInSeconds": {
           "type": "integer",
-          "format": "int64",
+          "format": "int32",
           "description": "Code execution timeout in seconds."
         }
       },
@@ -1120,7 +1120,7 @@
       "type": "string",
       "minLength": 1,
       "maxLength": 256,
-      "pattern": "^[A-Za-z0-9-_]{1,256}$",
+      "pattern": "^[a-zA-Z0-9_|}{\\[\\]\\:\"\";'<>?\\/.,@#$%\\^&*()_\\-+=!~`]{4,128}$",
       "x-ms-parameter-location": "method"
     },
     "SessionResourceFilePathQueryParameter": {