diff --git a/specs/activity/schema/activity-protocol.schema.json b/specs/activity/schema/activity-protocol.schema.json
new file mode 100644
index 00000000..a542cd7d
--- /dev/null
+++ b/specs/activity/schema/activity-protocol.schema.json
@@ -0,0 +1,826 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://raw.githubusercontent.com/microsoft/botframework-sdk/main/specs/activity/protocol-activity.schema.json",
+  "title": "Activity",
+  "description": "An Activity is the basic communication type for the Bot Framework 3.0 protocol.",
+  "type": "object",
+  "discriminator": {
+    "propertyName": "type"
+  },
+  "oneOf": [
+    {
+      "$ref": "#/definitions/message"
+    },
+    {
+      "$ref": "#/definitions/contactRelationUpdate"
+    },
+    {
+      "$ref": "#/definitions/conversationUpdate"
+    },
+    {
+      "$ref": "#/definitions/typing"
+    },
+    {
+      "$ref": "#/definitions/endOfConversation"
+    },
+    {
+      "$ref": "#/definitions/event"
+    },
+    {
+      "$ref": "#/definitions/invoke"
+    },
+    {
+      "$ref": "#/definitions/messageUpdate"
+    },
+    {
+      "$ref": "#/definitions/messageDelete"
+    },
+    {
+      "$ref": "#/definitions/installationUpdate"
+    },
+    {
+      "$ref": "#/definitions/messageReaction"
+    },
+    {
+      "$ref": "#/definitions/suggestion"
+    },
+    {
+      "$ref": "#/definitions/trace"
+    },
+    {
+      "$ref": "#/definitions/handoff"
+    }
+  ],
+  "definitions": {
+    "activity": {
+      "type": "object",
+      "properties": {
+        "type": {
+          "type": "string",
+          "description": "The type of the activity."
+        },
+        "id": {
+          "type": "string",
+          "description": "The unique identifier for the activity."
+        },
+        "timestamp": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The UTC timestamp of the activity."
+        },
+        "localTimestamp": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The local timestamp of the activity."
+        },
+        "localTimezone": {
+          "type": "string",
+          "description": "The timezone of the local timestamp."
+        },
+        "callerId": {
+          "type": "string",
+          "description": "The caller ID."
+        },
+        "serviceUrl": {
+          "type": "string",
+          "description": "The URL of the service."
+        },
+        "channelId": {
+          "type": "string",
+          "description": "The ID of the channel."
+        },
+        "from": {
+          "$ref": "#/definitions/channelAccount",
+          "description": "The sender of the activity."
+        },
+        "conversation": {
+          "$ref": "#/definitions/conversationAccount",
+          "description": "The conversation the activity is part of."
+        },
+        "recipient": {
+          "$ref": "#/definitions/channelAccount",
+          "description": "The recipient of the activity."
+        },
+        "entities": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/entity"
+          },
+          "description": "The entities of the activity."
+        },
+        "channelData": {
+          "type": "object",
+          "description": "The channel-specific data."
+        },
+        "replyToId": {
+          "type": "string",
+          "description": "The ID of the activity to reply to."
+        }
+      },
+      "required": [
+        "type",
+        "channelId",
+        "from",
+        "conversation",
+        "recipient",
+        "serviceUrl"
+      ]
+    },
+    "messageBase": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "locale": {
+          "type": "string",
+          "description": "The locale of the activity."
+        },
+        "text": {
+          "type": "string",
+          "description": "The text of the activity."
+        },
+        "textFormat": {
+          "type": "string",
+          "description": "The format of the text.",
+          "enum": [
+            "plain",
+            "markdown",
+            "xml"
+          ]
+        },
+        "speak": {
+          "type": "string",
+          "description": "The text to be spoken."
+        },
+        "inputHint": {
+          "type": "string",
+          "description": "A hint for the input.",
+          "enum": [
+            "accepting",
+            "expecting",
+            "ignoring"
+          ]
+        },
+        "summary": {
+          "type": "string",
+          "description": "A summary of the activity."
+        },
+        "suggestedActions": {
+          "$ref": "#/definitions/suggestedActions",
+          "description": "The suggested actions for the activity."
+        },
+        "attachments": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/attachment"
+          },
+          "description": "The attachments of the activity."
+        },
+        "attachmentLayout": {
+          "type": "string",
+          "description": "The layout of the attachments.",
+          "enum": [
+            "list",
+            "carousel"
+          ]
+        },
+        "value": {
+          "type": "object",
+          "description": "The value of the activity."
+        },
+        "expiration": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The expiration time of the activity."
+        },
+        "importance": {
+          "type": "string",
+          "description": "The importance of the activity.",
+          "enum": [
+            "low",
+            "normal",
+            "high"
+          ]
+        },
+        "deliveryMode": {
+          "type": "string",
+          "description": "The delivery mode of the activity.",
+          "enum": [
+            "normal",
+            "notification",
+            "expectReplies"
+          ]
+        },
+        "listenFor": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "A list of phrases to listen for."
+        },
+        "semanticAction": {
+          "$ref": "#/definitions/semanticAction",
+          "description": "The semantic action of the activity."
+        }
+      }
+    },
+    "message": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/messageBase"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "message"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "contactRelationUpdate": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "contactRelationUpdate"
+          ]
+        },
+        "action": {
+          "type": "string",
+          "enum": [
+            "add",
+            "remove"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "conversationUpdate": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "conversationUpdate"
+          ]
+        },
+        "membersAdded": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/channelAccount"
+          },
+          "description": "The members added to the conversation."
+        },
+        "membersRemoved": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/channelAccount"
+          },
+          "description": "The members removed from the conversation."
+        },
+        "topicName": {
+          "type": "string",
+          "description": "The name of the topic."
+        },
+        "historyDisclosed": {
+          "type": "boolean",
+          "description": "Indicates if the history is disclosed."
+        }
+      },
+      "required": [ "type" ]
+    },
+    "typing": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "typing"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "endOfConversation": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "endOfConversation"
+          ]
+        },
+        "code": {
+          "type": "string",
+          "description": "The code of the activity."
+        },
+        "text": {
+          "type": "string",
+          "description": "The text of the activity."
+        }
+      },
+      "required": [ "type" ]
+    },
+    "event": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "event"
+          ]
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the activity."
+        },
+        "value": {
+          "type": "object",
+          "description": "The value of the activity."
+        },
+        "relatesTo": {
+          "$ref": "#/definitions/conversationReference",
+          "description": "A reference to another conversation."
+        }
+      },
+      "required": [
+        "type",
+        "name"
+      ]
+    },
+    "invoke": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "invoke"
+          ]
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the activity."
+        },
+        "value": {
+          "type": "object",
+          "description": "The value of the activity."
+        },
+        "relatesTo": {
+          "$ref": "#/definitions/conversationReference",
+          "description": "A reference to another conversation."
+        }
+      },
+      "required": [
+        "type",
+        "name"
+      ]
+    },
+    "messageUpdate": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/messageBase"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "messageUpdate"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "messageDelete": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "messageDelete"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "installationUpdate": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "installationUpdate"
+          ]
+        },
+        "action": {
+          "type": "string",
+          "enum": [
+            "add",
+            "remove"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "messageReaction": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "messageReaction"
+          ]
+        },
+        "reactionsAdded": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/messageReactionObject"
+          },
+          "description": "The reactions added to the activity."
+        },
+        "reactionsRemoved": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/messageReactionObject"
+          },
+          "description": "The reactions removed from the activity."
+        }
+      },
+      "required": [ "type" ]
+    },
+    "suggestion": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/messageBase"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "suggestion"
+          ]
+        },
+        "textHighlights": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/textHighlight"
+          },
+          "description": "The text highlights of the activity."
+        }
+      },
+      "required": [ "type" ]
+    },
+    "trace": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "trace"
+          ]
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the activity."
+        },
+        "label": {
+          "type": "string",
+          "description": "The label of the activity."
+        },
+        "valueType": {
+          "type": "string",
+          "description": "The type of the value."
+        },
+        "value": {
+          "type": "object",
+          "description": "The value of the activity."
+        },
+        "relatesTo": {
+          "$ref": "#/definitions/conversationReference",
+          "description": "A reference to another conversation."
+        }
+      },
+      "required": [ "type" ]
+    },
+    "handoff": {
+      "type": "object",
+      "allOf": [
+        {
+          "$ref": "#/definitions/activity"
+        }
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "handoff"
+          ]
+        }
+      },
+      "required": [ "type" ]
+    },
+    "channelAccount": {
+      "type": "object",
+      "properties": {
+        "id": {
+          "type": "string",
+          "description": "The ID of the channel account."
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the channel account."
+        },
+        "aadObjectId": {
+          "type": "string",
+          "description": "The Azure Active Directory object ID of the channel account."
+        },
+        "role": {
+          "type": "string",
+          "description": "The role of the channel account.",
+          "enum": [
+            "user",
+            "bot"
+          ]
+        }
+      },
+      "required": [
+        "id"
+      ]
+    },
+    "conversationAccount": {
+      "type": "object",
+      "properties": {
+        "isGroup": {
+          "type": "boolean",
+          "description": "Indicates if the conversation is a group conversation."
+        },
+        "conversationType": {
+          "type": "string",
+          "description": "The type of the conversation."
+        },
+        "id": {
+          "type": "string",
+          "description": "The ID of the conversation."
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the conversation."
+        },
+        "aadObjectId": {
+          "type": "string",
+          "description": "The Azure Active Directory object ID of the conversation."
+        },
+        "role": {
+          "type": "string",
+          "description": "The role of the conversation account.",
+          "enum": [
+            "user",
+            "bot"
+          ]
+        },
+        "tenantId": {
+          "type": "string",
+          "description": "The tenant ID of the conversation."
+        }
+      },
+      "required": [
+        "id"
+      ]
+    },
+    "messageReactionObject": {
+      "type": "object",
+      "properties": {
+        "type": {
+          "type": "string",
+          "description": "The type of the message reaction."
+        }
+      }
+    },
+    "suggestedActions": {
+      "type": "object",
+      "properties": {
+        "to": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          },
+          "description": "The recipients of the suggested actions."
+        },
+        "actions": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/cardAction"
+          },
+          "description": "The suggested actions."
+        }
+      }
+    },
+    "attachment": {
+      "type": "object",
+      "properties": {
+        "contentType": {
+          "type": "string",
+          "description": "The content type of the attachment."
+        },
+        "contentUrl": {
+          "type": "string",
+          "description": "The URL of the attachment content."
+        },
+        "content": {
+          "type": "object",
+          "description": "The content of the attachment."
+        },
+        "name": {
+          "type": "string",
+          "description": "The name of the attachment."
+        },
+        "thumbnailUrl": {
+          "type": "string",
+          "description": "The URL of the attachment thumbnail."
+        }
+      }
+    },
+    "entity": {
+      "type": "object",
+      "properties": {
+        "type": {
+          "type": "string",
+          "description": "The type of the entity."
+        }
+      }
+    },
+    "conversationReference": {
+      "type": "object",
+      "properties": {
+        "activityId": {
+          "type": "string",
+          "description": "The ID of the activity."
+        },
+        "user": {
+          "$ref": "#/definitions/channelAccount",
+          "description": "The user."
+        },
+        "bot": {
+          "$ref": "#/definitions/channelAccount",
+          "description": "The bot."
+        },
+        "conversation": {
+          "$ref": "#/definitions/conversationAccount",
+          "description": "The conversation."
+        },
+        "channelId": {
+          "type": "string",
+          "description": "The ID of the channel."
+        },
+        "serviceUrl": {
+          "type": "string",
+          "description": "The URL of the service."
+        },
+        "locale": {
+          "type": "string",
+          "description": "The locale."
+        }
+      }
+    },
+    "textHighlight": {
+      "type": "object",
+      "properties": {
+        "text": {
+          "type": "string",
+          "description": "The text to highlight."
+        },
+        "occurrence": {
+          "type": "integer",
+          "description": "The occurrence of the text to highlight."
+        }
+      }
+    },
+    "cardAction": {
+      "type": "object",
+      "properties": {
+        "type": {
+          "type": "string",
+          "description": "The type of the card action.",
+          "enum": [
+            "openUrl",
+            "imBack",
+            "postBack",
+            "playAudio",
+            "playVideo",
+            "showImage",
+            "downloadFile",
+            "signin",
+            "call",
+            "messageBack"
+          ]
+        },
+        "title": {
+          "type": "string",
+          "description": "The title of the card action."
+        },
+        "image": {
+          "type": "string",
+          "description": "The image of the card action."
+        },
+        "text": {
+          "type": "string",
+          "description": "The text of the card action."
+        },
+        "displayText": {
+          "type": "string",
+          "description": "The display text of the card action."
+        },
+        "value": {
+          "type": "string",
+          "description": "The value of the card action."
+        },
+        "channelData": {
+          "type": "object",
+          "description": "The channel-specific data."
+        }
+      }
+    },
+    "semanticAction": {
+      "type": "object",
+      "properties": {
+        "id": {
+          "type": "string",
+          "description": "The ID of the semantic action."
+        },
+        "entities": {
+          "type": "object",
+          "description": "The entities of the semantic action."
+        },
+        "state": {
+          "type": "string",
+          "enum": [
+            "start",
+            "continue",
+            "done"
+          ]
+        }
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/specs/activity/schema/validator/csharp/Program.cs b/specs/activity/schema/validator/csharp/Program.cs
new file mode 100644
index 00000000..ec0e1188
--- /dev/null
+++ b/specs/activity/schema/validator/csharp/Program.cs
@@ -0,0 +1,130 @@
+using NJsonSchema;
+using NJsonSchema.Validation;
+using Newtonsoft.Json.Linq;
+
+static async Task<JsonSchema> LoadSchemaAsync(string schemaPath) => await JsonSchema.FromFileAsync(schemaPath);
+
+string schemaFile = Path.Combine(AppContext.BaseDirectory, "activity.schema.json");
+if (!File.Exists(schemaFile))
+{
+    Console.ForegroundColor = ConsoleColor.Red;
+    Console.WriteLine($"Schema file not found: {schemaFile}");
+    Console.ResetColor();
+    return;
+}
+
+// Discover example files relative to project root (navigate up to validator folder structure)
+// Expect examples under ../examples/json
+string? baseDir = AppContext.BaseDirectory;
+// Try to locate examples directory by walking up a few levels
+string? examplesDir = null;
+var current = new DirectoryInfo(baseDir);
+for (int i = 0; i < 6 && current != null; i++)
+{
+    var probe = Path.Combine(current.FullName, "examples", "json");
+    if (Directory.Exists(probe)) { examplesDir = probe; break; }
+    current = current.Parent;
+}
+
+if (examplesDir == null)
+{
+    Console.ForegroundColor = ConsoleColor.Yellow;
+    Console.WriteLine("Examples directory not found (expected ../examples/json). Will fall back to input.json if present.");
+    Console.ResetColor();
+}
+
+var schema = await LoadSchemaAsync(schemaFile);
+
+List<(string name, JToken instance)> instances = new();
+
+if (examplesDir != null)
+{
+    foreach (var file in Directory.GetFiles(examplesDir, "*.json", SearchOption.TopDirectoryOnly).OrderBy(f => f))
+    {
+        try
+        {
+            var text = File.ReadAllText(file);
+            instances.Add((Path.GetFileName(file), JToken.Parse(text)));
+        }
+        catch (Exception ex)
+        {
+            Console.ForegroundColor = ConsoleColor.Red;
+            Console.WriteLine($"Failed to parse {file}: {ex.Message}");
+            Console.ResetColor();
+        }
+    }
+}
+
+// Backward compatibility: single input.json
+string singleInput = Path.Combine(AppContext.BaseDirectory, "input.json");
+if (File.Exists(singleInput))
+{
+    try
+    {
+        instances.Add(("input.json", JToken.Parse(File.ReadAllText(singleInput))));
+    }
+    catch (Exception ex)
+    {
+        Console.ForegroundColor = ConsoleColor.Red;
+        Console.WriteLine("input.json parse error: " + ex.Message);
+        Console.ResetColor();
+    }
+}
+
+if (instances.Count == 0)
+{
+    Console.ForegroundColor = ConsoleColor.Yellow;
+    Console.WriteLine("No JSON instances found to validate.");
+    Console.ResetColor();
+    return;
+}
+
+int total = 0;
+int failures = 0;
+
+foreach (var (name, token) in instances)
+{
+    total++;
+    var errors = schema.Validate(token);
+    if (errors.Count == 0)
+    {
+        Console.ForegroundColor = ConsoleColor.Green;
+        Console.WriteLine($"[OK] {name} ({token["type"] ?? "unknown-type"})");
+        Console.ResetColor();
+    }
+    else
+    {
+        failures++;
+        Console.ForegroundColor = ConsoleColor.Yellow;
+        Console.WriteLine($"[FAIL] {name} ({token["type"] ?? "unknown-type"}) - {errors.Count} error(s)");
+        Console.ResetColor();
+        int i = 1;
+        foreach (var e in errors)
+        {
+            Console.ForegroundColor = ConsoleColor.Red;
+            Console.WriteLine($"  [{i}] {e.Kind}");
+            Console.ResetColor();
+            Console.WriteLine($"     Path    : {(string.IsNullOrEmpty(e.Path) ? "$" : "$" + e.Path)}");
+            Console.WriteLine($"     Detail  : {e}");
+            if (!string.IsNullOrEmpty(e.Property))
+                Console.WriteLine($"     Property: {e.Property}");
+            i++;
+        }
+    }
+}
+
+Console.WriteLine();
+Console.WriteLine($"Summary: {total - failures} valid / {failures} invalid / {total} total");
+if (failures == 0)
+{
+    Console.ForegroundColor = ConsoleColor.Green;
+    Console.WriteLine("All examples are valid.");
+    Console.ResetColor();
+}
+else
+{
+    Console.ForegroundColor = ConsoleColor.Red;
+    Console.WriteLine("Some examples failed validation.");
+    Console.ResetColor();
+    Environment.ExitCode = 1;
+}
\ No newline at end of file
diff --git a/specs/activity/schema/validator/csharp/SchemaValidator.csproj b/specs/activity/schema/validator/csharp/SchemaValidator.csproj
new file mode 100644
index 00000000..0f7062ce
--- /dev/null
+++ b/specs/activity/schema/validator/csharp/SchemaValidator.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+	<OutputType>Exe</OutputType>
+	<TargetFramework>net8.0</TargetFramework>
+	<ImplicitUsings>enable</ImplicitUsings>
+	<Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+	<PackageReference Include="NJsonSchema" Version="11.5.0" />
+  </ItemGroup>
+
+</Project>
diff --git a/specs/activity/schema/validator/csharp/SchemaValidator.sln b/specs/activity/schema/validator/csharp/SchemaValidator.sln
new file mode 100644
index 00000000..101d0469
--- /dev/null
+++ b/specs/activity/schema/validator/csharp/SchemaValidator.sln
@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.14.36414.22 d17.14
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SchemaValidator", "SchemaValidator.csproj", "{2F44ACFB-7A40-4433-8D58-476B682C7AF7}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{2F44ACFB-7A40-4433-8D58-476B682C7AF7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2F44ACFB-7A40-4433-8D58-476B682C7AF7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2F44ACFB-7A40-4433-8D58-476B682C7AF7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2F44ACFB-7A40-4433-8D58-476B682C7AF7}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {833ED1E0-B359-4969-936C-1C5ED1B6803F}
+	EndGlobalSection
+EndGlobal
diff --git a/specs/activity/schema/validator/examples/json/01-message.json b/specs/activity/schema/validator/examples/json/01-message.json
new file mode 100644
index 00000000..fab119d7
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/01-message.json
@@ -0,0 +1,38 @@
+{
+  "type": "message",
+  "id": "message-activity-1",
+  "timestamp": "2025-09-15T10:00:01.000Z",
+  "localTimestamp": "2025-09-15T03:00:01.000-07:00",
+  "localTimezone": "America/Los_Angeles",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "isGroup": true, "id": "conv-1", "name": "Project Discussion" },
+  "recipient": { "id": "bot-id-1", "name": "HelpBot" },
+  "text": "Hello, I need help with my order.",
+  "textFormat": "plain",
+  "locale": "en-US",
+  "attachments": [
+    {
+      "contentType": "application/vnd.microsoft.card.hero",
+      "content": {
+        "title": "Order #12345",
+        "text": "Status: Shipped"
+      }
+    }
+  ],
+  "suggestedActions": {
+    "actions": [
+      {
+        "type": "imBack",
+        "title": "Track Package",
+        "value": "track order 12345"
+      },
+      {
+        "type": "imBack",
+        "title": "Cancel Order",
+        "value": "cancel order 12345"
+      }
+    ]
+  }
+}
diff --git a/specs/activity/schema/validator/examples/json/02-contactRelationUpdate.json b/specs/activity/schema/validator/examples/json/02-contactRelationUpdate.json
new file mode 100644
index 00000000..4385c25a
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/02-contactRelationUpdate.json
@@ -0,0 +1,11 @@
+{
+  "type": "contactRelationUpdate",
+  "id": "contact-relation-update-1",
+  "timestamp": "2025-09-15T10:00:02.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "skype",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-2" },
+  "recipient": { "id": "bot-id-1", "name": "WelcomeBot" },
+  "action": "add"
+}
diff --git a/specs/activity/schema/validator/examples/json/03-conversationUpdate.json b/specs/activity/schema/validator/examples/json/03-conversationUpdate.json
new file mode 100644
index 00000000..8f31bb22
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/03-conversationUpdate.json
@@ -0,0 +1,13 @@
+{
+  "type": "conversationUpdate",
+  "id": "conversation-update-1",
+  "timestamp": "2025-09-15T10:00:03.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-2", "name": "Jane Smith" },
+  "conversation": { "isGroup": true, "id": "conv-1", "name": "Project Discussion" },
+  "recipient": { "id": "bot-id-1", "name": "HelpBot" },
+  "membersAdded": [ { "id": "user-id-3", "name": "Sam Brown" } ],
+  "membersRemoved": [],
+  "topicName": "Project Discussion Kickoff"
+}
diff --git a/specs/activity/schema/validator/examples/json/04-typing.json b/specs/activity/schema/validator/examples/json/04-typing.json
new file mode 100644
index 00000000..a085fed1
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/04-typing.json
@@ -0,0 +1,10 @@
+{
+  "type": "typing",
+  "id": "typing-1",
+  "timestamp": "2025-09-15T10:00:04.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "webchat",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-3" },
+  "recipient": { "id": "bot-id-1", "name": "EchoBot" }
+}
diff --git a/specs/activity/schema/validator/examples/json/05-endOfConversation.json b/specs/activity/schema/validator/examples/json/05-endOfConversation.json
new file mode 100644
index 00000000..d612a606
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/05-endOfConversation.json
@@ -0,0 +1,12 @@
+{
+  "type": "endOfConversation",
+  "id": "end-of-conv-1",
+  "timestamp": "2025-09-15T10:00:05.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "bot-id-1", "name": "SurveyBot" },
+  "conversation": { "id": "conv-4" },
+  "recipient": { "id": "user-id-4", "name": "Peter Jones" },
+  "code": "completedSuccessfully",
+  "text": "Thanks for completing the survey!"
+}
diff --git a/specs/activity/schema/validator/examples/json/06-event.json b/specs/activity/schema/validator/examples/json/06-event.json
new file mode 100644
index 00000000..5e6a504d
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/06-event.json
@@ -0,0 +1,12 @@
+{
+  "type": "event",
+  "id": "event-1",
+  "timestamp": "2025-09-15T10:00:06.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "webchat",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-5" },
+  "recipient": { "id": "bot-id-1", "name": "LocationBot" },
+  "name": "locationReceived",
+  "value": { "latitude": 47.6062, "longitude": -122.3321 }
+}
diff --git a/specs/activity/schema/validator/examples/json/07-invoke.json b/specs/activity/schema/validator/examples/json/07-invoke.json
new file mode 100644
index 00000000..ca29e277
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/07-invoke.json
@@ -0,0 +1,12 @@
+{
+  "type": "invoke",
+  "id": "invoke-1",
+  "timestamp": "2025-09-15T10:00:07.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-6" },
+  "recipient": { "id": "bot-id-1", "name": "TaskBot" },
+  "name": "task/submit",
+  "value": { "taskId": "task-987", "data": { "comments": "All done." } }
+}
diff --git a/specs/activity/schema/validator/examples/json/08-messageUpdate.json b/specs/activity/schema/validator/examples/json/08-messageUpdate.json
new file mode 100644
index 00000000..b4cf0870
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/08-messageUpdate.json
@@ -0,0 +1,12 @@
+{
+  "type": "messageUpdate",
+  "id": "message-activity-1",
+  "timestamp": "2025-09-15T10:00:08.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-1" },
+  "recipient": { "id": "bot-id-1", "name": "HelpBot" },
+  "text": "Hello, I need help with my order #12345.",
+  "locale": "en-US"
+}
diff --git a/specs/activity/schema/validator/examples/json/09-messageDelete.json b/specs/activity/schema/validator/examples/json/09-messageDelete.json
new file mode 100644
index 00000000..44b86ce9
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/09-messageDelete.json
@@ -0,0 +1,10 @@
+{
+  "type": "messageDelete",
+  "id": "message-activity-to-delete",
+  "timestamp": "2025-09-15T10:00:09.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-1", "name": "John Doe" },
+  "conversation": { "id": "conv-1" },
+  "recipient": { "id": "bot-id-1", "name": "HelpBot" }
+}
diff --git a/specs/activity/schema/validator/examples/json/10-installationUpdate.json b/specs/activity/schema/validator/examples/json/10-installationUpdate.json
new file mode 100644
index 00000000..09f494d6
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/10-installationUpdate.json
@@ -0,0 +1,11 @@
+{
+  "type": "installationUpdate",
+  "id": "install-update-1",
+  "timestamp": "2025-09-15T10:00:10.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-admin", "name": "Admin User" },
+  "conversation": { "id": "conv-tenant-level" },
+  "recipient": { "id": "bot-id-1", "name": "AdminBot" },
+  "action": "add"
+}
diff --git a/specs/activity/schema/validator/examples/json/11-messageReaction.json b/specs/activity/schema/validator/examples/json/11-messageReaction.json
new file mode 100644
index 00000000..1cb415fe
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/11-messageReaction.json
@@ -0,0 +1,13 @@
+{
+  "type": "messageReaction",
+  "id": "reaction-1",
+  "timestamp": "2025-09-15T10:00:11.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "msteams",
+  "from": { "id": "user-id-2", "name": "Jane Smith" },
+  "conversation": { "id": "conv-1" },
+  "recipient": { "id": "bot-id-1", "name": "HelpBot" },
+  "replyToId": "message-activity-1",
+  "reactionsAdded": [ { "type": "like" } ],
+  "reactionsRemoved": []
+}
diff --git a/specs/activity/schema/validator/examples/json/12-suggestion.json b/specs/activity/schema/validator/examples/json/12-suggestion.json
new file mode 100644
index 00000000..6b68ad16
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/12-suggestion.json
@@ -0,0 +1,13 @@
+{
+  "type": "suggestion",
+  "id": "suggestion-1",
+  "timestamp": "2025-09-15T10:00:12.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "cortana",
+  "from": { "id": "bot-id-1", "name": "CalendarBot" },
+  "conversation": { "id": "conv-7" },
+  "recipient": { "id": "user-id-1", "name": "John Doe" },
+  "replyToId": "original-message-id",
+  "text": "I can create that meeting for you.",
+  "textHighlights": [ { "text": "meet on Monday", "occurrence": 1 } ]
+}
diff --git a/specs/activity/schema/validator/examples/json/13-trace.json b/specs/activity/schema/validator/examples/json/13-trace.json
new file mode 100644
index 00000000..94d6e9bb
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/13-trace.json
@@ -0,0 +1,18 @@
+{
+  "type": "trace",
+  "id": "trace-1",
+  "timestamp": "2025-09-15T10:00:13.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "emulator",
+  "from": { "id": "bot-id-1", "name": "DebuggingBot" },
+  "conversation": { "id": "conv-debug" },
+  "recipient": { "id": "user-id-dev", "name": "Developer" },
+  "name": "LUIS_TRACE",
+  "label": "LUIS Trace",
+  "valueType": "https://www.luis.ai/schemas/trace",
+  "value": {
+    "query": "book a flight to paris",
+    "topScoringIntent": { "intent": "BookFlight", "score": 0.98 },
+    "entities": [ { "type": "Location", "entity": "paris" } ]
+  }
+}
diff --git a/specs/activity/schema/validator/examples/json/14-handoff.json b/specs/activity/schema/validator/examples/json/14-handoff.json
new file mode 100644
index 00000000..35e86e3d
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/14-handoff.json
@@ -0,0 +1,11 @@
+{
+  "type": "handoff",
+  "id": "handoff-1",
+  "timestamp": "2025-09-15T10:00:14.000Z",
+  "serviceUrl": "https://smba.trafficmanager.net/amer/",
+  "channelId": "custom-channel",
+  "from": { "id": "bot-id-1", "name": "TriageBot" },
+  "conversation": { "id": "conv-8" },
+  "recipient": { "id": "human-agent-system", "name": "Live Agent Hub" },
+  "value": { "reason": "User requested human agent", "transcript": [ "User: I need to speak to a person.", "Bot: OK, I'll connect you to a live agent." ] }
+}
diff --git a/specs/activity/schema/validator/examples/json/15-simple-message.json b/specs/activity/schema/validator/examples/json/15-simple-message.json
new file mode 100644
index 00000000..6b631190
--- /dev/null
+++ b/specs/activity/schema/validator/examples/json/15-simple-message.json
@@ -0,0 +1,9 @@
+{
+  "type": "message",
+  "channelId": "emulator",
+  "from": { "id": "user1", "name": "User One" },
+  "conversation": { "id": "conv1", "name": "Conversation 1" },
+  "recipient": { "id": "bot", "name": "Bot" },
+  "serviceUrl": "https://example.org",
+  "text": "Hello, world!"
+}
diff --git a/specs/activity/schema/validator/js/README.md b/specs/activity/schema/validator/js/README.md
new file mode 100644
index 00000000..60eea49b
--- /dev/null
+++ b/specs/activity/schema/validator/js/README.md
@@ -0,0 +1,106 @@
+# Activity Schema Validator (JavaScript)
+
+This directory contains a lightweight validation script for the Activity Protocol schema. It compiles the JSON Schema with Ajv and validates all embedded JSON examples found in `activity-examples.md`.
+
+## Contents
+
+- `validate-activity.js` – Loads `activity-protocol.schema.json`, extracts JSON code blocks from `activity-examples.md`, and validates each example.
+- `README.md` – This documentation.
+
+## Prerequisites
+
+- Node.js 18+ (supports ES Modules & top-level features used here)
+- Dependencies: `ajv`, `ajv-formats`
+
+Install (from the repo root or this folder):
+
+```bash
+npm install ajv ajv-formats --save-dev
+```
+
+> If a top-level `package.json` already exists (it does in this repo), you can just install once at the root and run the script from this subfolder.
+
+## Running the Validator
+
+From this directory:
+
+```bash
+node validate-activity.js
+```
+
+You can also run from the repo root:
+
+```bash
+node specs/activity/schema/validator/js/validate-activity.js
+```
+
+Exit codes:
+- `0` – All examples are valid.
+- `1` – At least one example failed validation (errors printed to stderr).
+
+## How It Works
+
+1. Reads the schema at `../../activity-protocol.schema.json`.
+2. Compiles it with Ajv (draft-07, `discriminator` support enabled, all errors collected).
+3. Reads `../../activity-examples.md` and extracts every fenced block marked as:
+   ```
+   ```json
+   { ... }
+   ```
+   ```
+4. Parses each block to an object (ignoring blocks that don't parse).
+5. Validates each example and prints a per-example result plus a final summary.
+
+
+## Modifying the Schema
+
+When adding a new Activity type:
+
+1. Create a new definition under `definitions` (e.g., `"myCustomActivity"`).
+2. Give it a `properties.type.const` with its unique discriminator value.
+3. Add a `$ref` to it in the top-level `oneOf` array.
+4. Re-run the validator to ensure examples still pass.
+
+For additional message-like variants:
+
+- Reuse the shared `messageBase` (introduced to avoid conflicting `const` inheritance) via:
+  ```json
+  "allOf": [ { "$ref": "#/definitions/messageBase" } ]
+  ```
+  then add a `type.const` specific to your new variant.
+
+## Extending Example Extraction
+
+If you want to also validate examples stored as separate `.json` files, you could enhance `validate-activity.js`:
+
+```js
+// Pseudocode addition
+const examplesDir = path.join(__dirname, '../../examples');
+if (fs.existsSync(examplesDir)) {
+  for (const f of fs.readdirSync(examplesDir)) {
+    if (f.endsWith('.json')) {
+      examples.push(JSON.parse(fs.readFileSync(path.join(examplesDir,f), 'utf8')));
+    }
+  }
+}
+```
+
+## Troubleshooting
+
+| Problem | Likely Cause | Fix |
+|---------|--------------|-----|
+| `MODULE_NOT_FOUND: ajv` | Dependencies not installed | Run `npm install ajv ajv-formats` |
+| All examples suddenly failing | Schema syntax error | Validate schema JSON (e.g. with an online validator) |
+| Discriminator not selecting subtype | Missing `type.const` or absent subtype in `oneOf` | Add const + add `$ref` in `oneOf` |
+| ES Module import error | Older Node.js or `type` not set | Run with Node 18+; package root may need `{ "type": "module" }` |
+
+## License
+
+See the repository's top-level `LICENSE` (MIT).
+
+## Contributing
+
+Open a PR with schema changes plus updated examples. Ensure `node validate-activity.js` returns success.
+
+---
+Generated documentation.
diff --git a/specs/activity/schema/validator/js/validate-activity.js b/specs/activity/schema/validator/js/validate-activity.js
new file mode 100644
index 00000000..4570c90c
--- /dev/null
+++ b/specs/activity/schema/validator/js/validate-activity.js
@@ -0,0 +1,76 @@
+import fs from 'fs'
+import path from 'path'
+import Ajv from 'ajv'
+import addFormats from 'ajv-formats'
+
+const __dirname = path.dirname(new URL(import.meta.url).pathname.substring(1))
+
+// Initialize AJV
+const ajv = new Ajv({ allErrors: true, discriminator: true })
+addFormats(ajv)
+
+// Load the schema
+const schemaPath = path.join(__dirname, '../../activity-protocol.schema.json')
+const schema = JSON.parse(fs.readFileSync(schemaPath, 'utf8'))
+
+// Compile the schema
+const validate = ajv.compile(schema)
+
+// Collect examples from markdown
+const examples = []
+const mdExamplesPath = path.join(__dirname, '../../activity-examples.md')
+if (fs.existsSync(mdExamplesPath)) {
+  const examplesContent = fs.readFileSync(mdExamplesPath, 'utf8')
+  const codeBlockRegex = /```json\n([\s\S]*?)\n```/g
+  let match
+  while ((match = codeBlockRegex.exec(examplesContent)) !== null) {
+    try {
+      examples.push({ source: 'markdown', data: JSON.parse(match[1]) })
+    } catch (e) {
+      console.error('Failed to parse JSON example from markdown:', e)
+    }
+  }
+}
+
+// Collect standalone JSON example files
+const jsonExamplesDir = path.join(__dirname, '../examples/json')
+if (fs.existsSync(jsonExamplesDir)) {
+  for (const file of fs.readdirSync(jsonExamplesDir)) {
+    if (file.toLowerCase().endsWith('.json')) {
+      try {
+        const data = JSON.parse(fs.readFileSync(path.join(jsonExamplesDir, file), 'utf8'))
+        examples.push({ source: file, data })
+      } catch (e) {
+        console.error(`Failed to parse JSON example file ${file}:`, e)
+      }
+    }
+  }
+}
+
+if (examples.length === 0) {
+  console.warn('No examples found to validate.')
+  process.exit(0)
+}
+
+// Validate each example
+let allValid = true
+examples.forEach((example, index) => {
+  const valid = validate(example.data)
+  const label = example.data.type || 'unknown'
+  const origin = example.source
+  if (valid) {
+    console.log(`Example ${index + 1} [${origin}] (${label}) is valid.`)
+  } else {
+    allValid = false
+    console.error(`Example ${index + 1} [${origin}] (${label}) is invalid:`)
+    console.error(validate.errors)
+  }
+  console.log('---')
+})
+
+if (allValid) {
+  console.log('All examples are valid!')
+} else {
+  console.error('Some examples are invalid.')
+  process.exit(1)
+}