diff --git a/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Authentication/McpApiKeyAuthenticationHandler.cs b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Authentication/McpApiKeyAuthenticationHandler.cs
index 00a2b8f..4818bbb 100644
--- a/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Authentication/McpApiKeyAuthenticationHandler.cs
+++ b/colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Infrastructure/Authentication/McpApiKeyAuthenticationHandler.cs
@@ -48,11 +48,12 @@ public class McpApiKeyAuthenticationHandler : AuthenticationHandler<McpApiKeyAut
         }
 
         // Create claims from validation result
+        // Note: Use "tenant_id" to match ITenantContext implementations that look for this claim name
         var claims = new List<Claim>
         {
             new(ClaimTypes.NameIdentifier, validationResult.UserId.ToString()),
             new("ApiKeyId", validationResult.ApiKeyId.ToString()),
-            new("TenantId", validationResult.TenantId.ToString()),
+            new("tenant_id", validationResult.TenantId.ToString()),
             new("UserId", validationResult.UserId.ToString()),
         };