diff --git a/.github/workflows/stage-2-test.yaml b/.github/workflows/stage-2-test.yaml
index 08cc6ae..e771596 100644
--- a/.github/workflows/stage-2-test.yaml
+++ b/.github/workflows/stage-2-test.yaml
@@ -91,6 +91,7 @@ jobs:
       - name: "Checkout code"
         uses: actions/checkout@v4
         with:
+          submodules: 'true'
           fetch-depth: 0 # Full history is needed to improving relevancy of reporting
       - name: "Perform static analysis"
         uses: ./.github/actions/perform-static-analysis
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..5c6205a
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,5 @@
+[submodule "src/dotnet-mesh-client"]
+	# path = src/Shared/dotnet-mesh-client
+	path = src/dotnet-mesh-client
+	url = https://github.com/NHSDigital/dotnet-mesh-client.git
+	branch = main
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
index 957d73f..b4bc0fd 100644
--- a/.vscode/extensions.json
+++ b/.vscode/extensions.json
@@ -1,5 +1,7 @@
 {
   "recommendations": [
+    "ms-azuretools.vscode-azurefunctions",
+    "ms-dotnettools.csharp",
     "alefragnani.bookmarks",
     "davidanson.vscode-markdownlint",
     "dbaeumer.vscode-eslint",
diff --git a/src/ServiceLayer.Mesh/Data/DesignTimeDbContextFactory.cs b/src/ServiceLayer.Mesh/Data/DesignTimeDbContextFactory.cs
new file mode 100644
index 0000000..569baf9
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Data/DesignTimeDbContextFactory.cs
@@ -0,0 +1,22 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+using ServiceLayer.Mesh.Data;
+
+namespace ParticipantManager.API.Data;
+
+public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<ServiceLayerDbContext>
+{
+    public ServiceLayerDbContext CreateDbContext(string[] args)
+    {
+        var connectionString = Environment.GetEnvironmentVariable("DatabaseConnectionString");
+        if (string.IsNullOrEmpty(connectionString))
+        {
+            throw new InvalidOperationException("Connection string 'DatabaseConnectionString' is not configured.");
+        }
+
+        var optionsBuilder = new DbContextOptionsBuilder<ServiceLayerDbContext>();
+        optionsBuilder.UseSqlServer(connectionString);
+
+        return new ServiceLayerDbContext(optionsBuilder.Options);
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Data/ServiceLayerDbConext.cs b/src/ServiceLayer.Mesh/Data/ServiceLayerDbConext.cs
new file mode 100644
index 0000000..de65f7e
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Data/ServiceLayerDbConext.cs
@@ -0,0 +1,17 @@
+using Microsoft.EntityFrameworkCore;
+using ServiceLayer.Mesh.Models;
+
+namespace ServiceLayer.Mesh.Data;
+
+public class ServiceLayerDbContext(DbContextOptions<ServiceLayerDbContext> options) : DbContext(options)
+{
+    public DbSet<MeshFile> MeshFiles { get; set; }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        // Configure relationships, keys, etc.
+        modelBuilder.Entity<MeshFile>().HasKey(p => p.FileId);
+        modelBuilder.Entity<MeshFile>().Property(e => e.Status).HasConversion<string>();
+        modelBuilder.Entity<MeshFile>().Property(e => e.FileType).HasConversion<string>();
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Functions/DiscoveryFunction.cs b/src/ServiceLayer.Mesh/Functions/DiscoveryFunction.cs
new file mode 100644
index 0000000..ae06365
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Functions/DiscoveryFunction.cs
@@ -0,0 +1,69 @@
+using Azure.Storage.Queues;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using NHS.MESH.Client.Contracts.Services;
+using ServiceLayer.Mesh.Data;
+using ServiceLayer.Mesh.Models;
+
+namespace ServiceLayer.Mesh.Functions
+{
+    public class DiscoveryFunction
+    {
+        private readonly ILogger _logger;
+        private readonly IMeshInboxService _meshInboxService;
+        private readonly ServiceLayerDbContext _serviceLayerDbContext;
+        private readonly QueueClient _queueClient;
+
+        public DiscoveryFunction(ILogger<DiscoveryFunction> logger, IMeshInboxService meshInboxService, ServiceLayerDbContext serviceLayerDbContext, QueueClient queueClient)
+        {
+            _logger = logger;
+            _meshInboxService = meshInboxService;
+            _serviceLayerDbContext = serviceLayerDbContext;
+            _queueClient = queueClient;
+        }
+
+        [Function("DiscoveryFunction")]
+        public async Task Run([TimerTrigger("%DiscoveryTimerExpression%")] TimerInfo myTimer)
+        {
+            _logger.LogInformation($"DiscoveryFunction started at: {DateTime.Now}");
+
+            var mailboxId = Environment.GetEnvironmentVariable("BSSMailBox")
+                ?? throw new InvalidOperationException($"Environment variable 'BSSMailBox' is not set or is empty.");
+
+            var response = await _meshInboxService.GetMessagesAsync(mailboxId);
+
+            _queueClient.CreateIfNotExists();
+
+            foreach (var messageId in response.Response.Messages)
+            {
+                using var transaction = await _serviceLayerDbContext.Database.BeginTransactionAsync();
+
+                var existing = await _serviceLayerDbContext.MeshFiles
+                    .AnyAsync(f => f.FileId == messageId);
+
+                if (!existing)
+                {
+                    _serviceLayerDbContext.MeshFiles.Add(new MeshFile
+                    {
+                        FileId = messageId,
+                        FileType = MeshFileType.NbssAppointmentEvents,
+                        MailboxId = mailboxId,
+                        Status = MeshFileStatus.Discovered,
+                        FirstSeenUtc = DateTime.UtcNow,
+                        LastUpdatedUtc = DateTime.UtcNow
+                    });
+
+                    await _serviceLayerDbContext.SaveChangesAsync();
+                    await transaction.CommitAsync();
+
+                    _queueClient.SendMessage(messageId);
+                }
+                else
+                {
+                    await transaction.RollbackAsync();
+                }
+            }
+        }
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.Designer.cs b/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.Designer.cs
new file mode 100644
index 0000000..9e7f7de
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.Designer.cs
@@ -0,0 +1,66 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using ServiceLayer.Mesh.Data;
+
+#nullable disable
+
+namespace ServiceLayer.Mesh.Migrations
+{
+    [DbContext(typeof(ServiceLayerDbContext))]
+    [Migration("20250512113115_InitialCreate")]
+    partial class InitialCreate
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "9.0.1")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("ServiceLayer.Mesh.Models.MeshFile", b =>
+                {
+                    b.Property<string>("FileId")
+                        .HasMaxLength(255)
+                        .HasColumnType("nvarchar(255)");
+
+                    b.Property<string>("BlobPath")
+                        .HasMaxLength(1024)
+                        .HasColumnType("nvarchar(1024)");
+
+                    b.Property<string>("FileType")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<DateTime>("FirstSeenUtc")
+                        .HasColumnType("datetime2");
+
+                    b.Property<DateTime>("LastUpdatedUtc")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("MailboxId")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("nvarchar(20)");
+
+                    b.HasKey("FileId");
+
+                    b.ToTable("MeshFiles");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.cs b/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.cs
new file mode 100644
index 0000000..630118f
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Migrations/20250512113115_InitialCreate.cs
@@ -0,0 +1,39 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ServiceLayer.Mesh.Migrations
+{
+    /// <inheritdoc />
+    public partial class InitialCreate : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "MeshFiles",
+                columns: table => new
+                {
+                    FileId = table.Column<string>(type: "nvarchar(255)", maxLength: 255, nullable: false),
+                    FileType = table.Column<string>(type: "nvarchar(50)", maxLength: 50, nullable: false),
+                    MailboxId = table.Column<string>(type: "nvarchar(50)", maxLength: 50, nullable: false),
+                    Status = table.Column<string>(type: "nvarchar(20)", maxLength: 20, nullable: false),
+                    BlobPath = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: true),
+                    FirstSeenUtc = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    LastUpdatedUtc = table.Column<DateTime>(type: "datetime2", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_MeshFiles", x => x.FileId);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "MeshFiles");
+        }
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Migrations/ServiceLayerDbContextModelSnapshot.cs b/src/ServiceLayer.Mesh/Migrations/ServiceLayerDbContextModelSnapshot.cs
new file mode 100644
index 0000000..71cedc3
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Migrations/ServiceLayerDbContextModelSnapshot.cs
@@ -0,0 +1,63 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using ServiceLayer.Mesh.Data;
+
+#nullable disable
+
+namespace ServiceLayer.Mesh.Migrations
+{
+    [DbContext(typeof(ServiceLayerDbContext))]
+    partial class ServiceLayerDbContextModelSnapshot : ModelSnapshot
+    {
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "9.0.1")
+                .HasAnnotation("Relational:MaxIdentifierLength", 128);
+
+            SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
+
+            modelBuilder.Entity("ServiceLayer.Mesh.Models.MeshFile", b =>
+                {
+                    b.Property<string>("FileId")
+                        .HasMaxLength(255)
+                        .HasColumnType("nvarchar(255)");
+
+                    b.Property<string>("BlobPath")
+                        .HasMaxLength(1024)
+                        .HasColumnType("nvarchar(1024)");
+
+                    b.Property<string>("FileType")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<DateTime>("FirstSeenUtc")
+                        .HasColumnType("datetime2");
+
+                    b.Property<DateTime>("LastUpdatedUtc")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("MailboxId")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("nvarchar(20)");
+
+                    b.HasKey("FileId");
+
+                    b.ToTable("MeshFiles");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/src/ServiceLayer.Mesh/Models/MeshFile.cs b/src/ServiceLayer.Mesh/Models/MeshFile.cs
new file mode 100644
index 0000000..b7de2cb
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Models/MeshFile.cs
@@ -0,0 +1,20 @@
+using System.ComponentModel.DataAnnotations;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
+
+namespace ServiceLayer.Mesh.Models;
+
+public class MeshFile
+{
+    [MaxLength(255)]
+    public required string FileId { get; set; }
+    [MaxLength(50)]
+    public required MeshFileType FileType { get; set; }
+    [MaxLength(50)]
+    public required string MailboxId { get; set; }
+    [MaxLength(20)]
+    public required MeshFileStatus Status { get; set; }
+    [MaxLength(1024)]
+    public string? BlobPath { get; set; }
+    public DateTime FirstSeenUtc { get; set; }
+    public DateTime LastUpdatedUtc { get; set; }
+}
diff --git a/src/ServiceLayer.Mesh/Models/MeshFileStatus.cs b/src/ServiceLayer.Mesh/Models/MeshFileStatus.cs
new file mode 100644
index 0000000..879abb9
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Models/MeshFileStatus.cs
@@ -0,0 +1,12 @@
+namespace ServiceLayer.Mesh.Models;
+
+public enum MeshFileStatus
+{
+    Discovered,
+    Extracting,
+    Extracted,
+    Transforming,
+    Transformed,
+    FailedExtract,
+    FailedTransform
+}
diff --git a/src/ServiceLayer.Mesh/Models/MeshFileType.cs b/src/ServiceLayer.Mesh/Models/MeshFileType.cs
new file mode 100644
index 0000000..c86748f
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Models/MeshFileType.cs
@@ -0,0 +1,6 @@
+namespace ServiceLayer.Mesh.Models;
+
+public enum MeshFileType
+{
+    NbssAppointmentEvents
+}
diff --git a/src/ServiceLayer.Mesh/Program.cs b/src/ServiceLayer.Mesh/Program.cs
new file mode 100644
index 0000000..4ae7a2d
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Program.cs
@@ -0,0 +1,64 @@
+using Microsoft.Azure.Functions.Worker.Builder;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Azure.Storage.Queues;
+using Azure.Identity;
+using Microsoft.EntityFrameworkCore;
+using NHS.MESH.Client;
+using ServiceLayer.Mesh.Data;
+
+var host = new HostBuilder()
+    .ConfigureFunctionsWebApplication()
+    .ConfigureServices(services =>
+    {
+        // MESH Client config
+        services
+            .AddMeshClient(_ => _.MeshApiBaseUrl = Environment.GetEnvironmentVariable("MeshApiBaseUrl"))
+            .AddMailbox(Environment.GetEnvironmentVariable("BSSMailBox"), new NHS.MESH.Client.Configuration.MailboxConfiguration
+            {
+                Password = Environment.GetEnvironmentVariable("MeshPassword"),
+                SharedKey = Environment.GetEnvironmentVariable("MeshSharedKey"),
+            }).Build();
+
+        // EF Core DbContext
+        services.AddDbContext<ServiceLayerDbContext>(options =>
+        {
+            var connectionString = Environment.GetEnvironmentVariable("DatabaseConnectionString");
+            if (string.IsNullOrEmpty(connectionString))
+                throw new InvalidOperationException("The connection string has not been initialized.");
+
+            options.UseSqlServer(connectionString);
+        });
+
+        // Register QueueClient as singleton
+        services.AddSingleton(provider =>
+        {
+            var environment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");
+
+            if (environment == "Development")
+            {
+                return new QueueClient("UseDevelopmentStorage=true", "my-local-queue");
+            }
+            else
+            {
+                var queueUrl = Environment.GetEnvironmentVariable("QueueUrl");
+
+                if (string.IsNullOrWhiteSpace(queueUrl))
+                {
+                    throw new InvalidOperationException("QueueUrl environment variable is not set.");
+                }
+
+                var credential = new ManagedIdentityCredential();
+                return new QueueClient(new Uri(queueUrl), credential);
+            }
+        });
+    });
+
+
+// Application Insights isn't enabled by default. See https://aka.ms/AAt8mw4.
+// builder.Services
+//     .AddApplicationInsightsTelemetryWorkerService()
+//     .ConfigureFunctionsApplicationInsights();
+
+var app = host.Build();
+await app.RunAsync();
diff --git a/src/ServiceLayer.Mesh/Properties/launchSettings.json b/src/ServiceLayer.Mesh/Properties/launchSettings.json
new file mode 100644
index 0000000..cd92488
--- /dev/null
+++ b/src/ServiceLayer.Mesh/Properties/launchSettings.json
@@ -0,0 +1,9 @@
+{
+  "profiles": {
+    "ServiceLayer.Mesh": {
+      "commandName": "Project",
+      "commandLineArgs": "--port 7142",
+      "launchBrowser": false
+    }
+  }
+}
diff --git a/src/ServiceLayer.Mesh/ServiceLayer.Mesh.csproj b/src/ServiceLayer.Mesh/ServiceLayer.Mesh.csproj
new file mode 100644
index 0000000..da05f0e
--- /dev/null
+++ b/src/ServiceLayer.Mesh/ServiceLayer.Mesh.csproj
@@ -0,0 +1,40 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
+    <OutputType>Exe</OutputType>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+    <PackageReference Include="Azure.Identity" Version="1.13.2" />
+    <PackageReference Include="Azure.Storage.Queues" Version="12.22.0" />
+    <!-- Application Insights isn't enabled by default. See https://aka.ms/AAt8mw4. -->
+    <!-- <PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.22.0" /> -->
+    <!-- <PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="2.0.0" /> -->
+    <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Timer" Version="4.3.1" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="2.0.0" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.1" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.1">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.1" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Update="host.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="local.settings.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
+    </None>
+  </ItemGroup>
+  <ItemGroup>
+    <Using Include="System.Threading.ExecutionContext" Alias="ExecutionContext" />
+    <ProjectReference Include="..\dotnet-mesh-client\application\DotNetMeshClient\NHS.Mesh.Client\NHS.Mesh.Client.csproj" />
+  </ItemGroup>
+</Project>
diff --git a/src/ServiceLayer.Mesh/host.json b/src/ServiceLayer.Mesh/host.json
new file mode 100644
index 0000000..2babc58
--- /dev/null
+++ b/src/ServiceLayer.Mesh/host.json
@@ -0,0 +1,12 @@
+{
+  "version": "2.0",
+  "logging": {
+    "applicationInsights": {
+      "samplingSettings": {
+        "isEnabled": true,
+        "excludedTypes": "Request"
+      },
+      "enableLiveMetricsFilters": true
+    }
+  }
+}
diff --git a/src/ServiceLayer.sln b/src/ServiceLayer.sln
index 0e4aad3..74ff958 100644
--- a/src/ServiceLayer.sln
+++ b/src/ServiceLayer.sln
@@ -9,48 +9,77 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tests", "Tests", "{0AB3BF05
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ServiceLayer.API.Tests", "..\tests\ServiceLayer.API.Tests\ServiceLayer.API.Tests.csproj", "{BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ServiceLayer.Mesh", "ServiceLayer.Mesh\ServiceLayer.Mesh.csproj", "{803E8A5E-A180-4799-8BE2-DD5BD3C34ED2}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ServiceLayer.Mesh.Tests", "..\tests\ServiceLayer.Mesh.Tests\ServiceLayer.Mesh.Tests.csproj", "{E5EF5B92-52DA-4EF3-956B-8AEE3D333428}"
+EndProject
 Global
-  GlobalSection(SolutionConfigurationPlatforms) = preSolution
-    Debug|Any CPU = Debug|Any CPU
-    Debug|x64 = Debug|x64
-    Debug|x86 = Debug|x86
-    Release|Any CPU = Release|Any CPU
-    Release|x64 = Release|x64
-    Release|x86 = Release|x86
-  EndGlobalSection
-  GlobalSection(ProjectConfigurationPlatforms) = postSolution
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-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Debug|x86.Build.0 = Debug|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|Any CPU.ActiveCfg = Release|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|Any CPU.Build.0 = Release|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|x64.ActiveCfg = Release|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|x64.Build.0 = Release|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|x86.ActiveCfg = Release|Any CPU
-    {BA052DAE-6FD1-483A-A0AF-DCBCF9E38C72}.Release|x86.Build.0 = Release|Any CPU
-  EndGlobalSection
-  GlobalSection(SolutionProperties) = preSolution
-    HideSolutionNode = FALSE
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diff --git a/src/dotnet-mesh-client b/src/dotnet-mesh-client
new file mode 160000
index 0000000..4e8846b
--- /dev/null
+++ b/src/dotnet-mesh-client
@@ -0,0 +1 @@
+Subproject commit 4e8846b8e6b3bb35bf29b25a2c1b91a5d07da1c2
diff --git a/tests/ServiceLayer.Mesh.Tests/Functions/DiscoveryFunctionTests.cs b/tests/ServiceLayer.Mesh.Tests/Functions/DiscoveryFunctionTests.cs
new file mode 100644
index 0000000..450f0aa
--- /dev/null
+++ b/tests/ServiceLayer.Mesh.Tests/Functions/DiscoveryFunctionTests.cs
@@ -0,0 +1,152 @@
+using System;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Xunit;
+using ServiceLayer.Mesh.Functions;
+using ServiceLayer.Mesh.Models;
+using ServiceLayer.Mesh.Data;
+using Microsoft.EntityFrameworkCore;
+using NHS.MESH.Client.Contracts.Services;
+using Microsoft.Azure.Functions.Worker;
+using NHS.MESH.Client.Models;
+using Azure.Storage.Queues;
+using Azure.Storage.Queues.Models;
+using Azure;
+
+public class DiscoveryFunctionTests
+{
+    private readonly Mock<ILogger<DiscoveryFunction>> _loggerMock;
+    private readonly Mock<IMeshInboxService> _meshInboxServiceMock;
+    private readonly ServiceLayerDbContext _dbContext;
+    private readonly Mock<QueueClient> _queueClientMock;
+    private readonly DiscoveryFunction _function;
+
+    public DiscoveryFunctionTests()
+    {
+        _loggerMock = new Mock<ILogger<DiscoveryFunction>>();
+        _meshInboxServiceMock = new Mock<IMeshInboxService>();
+        _queueClientMock = new Mock<QueueClient>();
+
+        var options = new DbContextOptionsBuilder<ServiceLayerDbContext>()
+            .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString())
+            .ConfigureWarnings(warnings =>
+                warnings.Ignore(Microsoft.EntityFrameworkCore.Diagnostics.InMemoryEventId.TransactionIgnoredWarning))
+            .Options;
+
+        _dbContext = new ServiceLayerDbContext(options);
+
+        Environment.SetEnvironmentVariable("MailboxId", "test-mailbox");
+        Environment.SetEnvironmentVariable("QueueUrl", "https://fakestorageaccount.queue.core.windows.net/testqueue");
+
+        _function = new DiscoveryFunction(
+            _loggerMock.Object,
+            _meshInboxServiceMock.Object,
+            _dbContext,
+            _queueClientMock.Object
+        );
+    }
+
+    [Fact]
+    public async Task Run_AddsNewMessageToDbAndQueue()
+    {
+        // Arrange
+        var testMessageId = "test-message-123";
+
+        _meshInboxServiceMock.Setup(s => s.GetMessagesAsync("test-mailbox"))
+            .ReturnsAsync(new MeshResponse<CheckInboxResponse>
+            {
+                Response = new CheckInboxResponse { Messages = new[] { testMessageId } }
+            });
+
+        // Act
+        await _function.Run(null);
+
+        // Assert
+        var meshFile = _dbContext.MeshFiles.FirstOrDefault(f => f.FileId == testMessageId);
+        Assert.NotNull(meshFile);
+        Assert.Equal(MeshFileStatus.Discovered, meshFile.Status);
+        Assert.Equal("test-mailbox", meshFile.MailboxId);
+
+        _queueClientMock.Verify(q => q.SendMessage(It.IsAny<string>()), Times.Once);
+    }
+
+    [Fact]
+    public async Task Run_DoesNotAddDuplicateMessageOrQueueIt()
+    {
+        // Arrange
+        var duplicateMessageId = "existing-message";
+        _dbContext.MeshFiles.Add(new MeshFile
+        {
+            FileId = duplicateMessageId,
+            FileType = MeshFileType.NbssAppointmentEvents,
+            MailboxId = "test-mailbox",
+            Status = MeshFileStatus.Discovered,
+            FirstSeenUtc = DateTime.UtcNow,
+            LastUpdatedUtc = DateTime.UtcNow
+        });
+        await _dbContext.SaveChangesAsync();
+
+        _meshInboxServiceMock.Setup(s => s.GetMessagesAsync("test-mailbox"))
+            .ReturnsAsync(new MeshResponse<CheckInboxResponse>
+            {
+                Response = new CheckInboxResponse { Messages = new[] { duplicateMessageId } }
+            });
+
+        // Act
+        await _function.Run(null);
+
+        // Assert
+        var count = _dbContext.MeshFiles.Count(f => f.FileId == duplicateMessageId);
+        Assert.Equal(1, count);
+
+        _queueClientMock.Verify(q => q.SendMessage(It.IsAny<string>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task Run_NoMessagesInInbox_DoesNothing()
+    {
+        // Arrange
+        _meshInboxServiceMock.Setup(s => s.GetMessagesAsync("test-mailbox"))
+            .ReturnsAsync(new MeshResponse<CheckInboxResponse>
+            {
+                Response = new CheckInboxResponse { Messages = Array.Empty<string>() }
+            });
+
+        // Act
+        await _function.Run(null);
+
+        // Assert
+        Assert.Empty(_dbContext.MeshFiles);
+        _queueClientMock.Verify(q => q.SendMessage(It.IsAny<string>()), Times.Never);
+    }
+
+    [Fact]
+    public async Task Run_MultipleMessagesInInbox_AllAreProcessed()
+    {
+        // Arrange
+        var messageIds = new[] { "msg-1", "msg-2", "msg-3" };
+
+        _meshInboxServiceMock.Setup(s => s.GetMessagesAsync("test-mailbox"))
+            .ReturnsAsync(new MeshResponse<CheckInboxResponse>
+            {
+                Response = new CheckInboxResponse { Messages = messageIds }
+            });
+
+        // Act
+        await _function.Run(null);
+
+        // Assert
+        foreach (var id in messageIds)
+        {
+            var meshFile = _dbContext.MeshFiles.FirstOrDefault(f => f.FileId == id);
+            Assert.NotNull(meshFile);
+            Assert.Equal(MeshFileStatus.Discovered, meshFile.Status);
+            Assert.Equal("test-mailbox", meshFile.MailboxId);
+        }
+
+        _queueClientMock.Verify(q => q.SendMessage(It.IsAny<string>()), Times.Exactly(messageIds.Length));
+    }
+}
diff --git a/tests/ServiceLayer.Mesh.Tests/ServiceLayer.Mesh.Tests.csproj b/tests/ServiceLayer.Mesh.Tests/ServiceLayer.Mesh.Tests.csproj
new file mode 100644
index 0000000..6c3d85a
--- /dev/null
+++ b/tests/ServiceLayer.Mesh.Tests/ServiceLayer.Mesh.Tests.csproj
@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="9.0.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../../src/ServiceLayer.Mesh/ServiceLayer.Mesh.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>