Added tests which guard the JSON of providers, the runtime, and services before source generation

app/MindWork AI Studio/Tools/Databases/VectorStore/QdrantEdgeClientImplementation.cs

@@ -215,31 +215,35 @@ public sealed class QdrantEdgeClientImplementation(
         return client;
     }
 
-    // ReSharper disable NotAccessedPositionalProperty.Local
-    private sealed record EnsureVectorStoreRequest(string StoreName, string DataSourceName, int VectorSize);
+    //
+    // The requests are internal rather than private, so that the JSON context of the runtime can name them. It
+    // generates the contracts they get written with, and a context sees no private type of another class.
+    //
+    // ReSharper disable NotAccessedPositionalProperty.Global
+    internal sealed record EnsureVectorStoreRequest(string StoreName, string DataSourceName, int VectorSize);
 
-    private sealed record CheckVectorStoreRequest(string StoreName);
+    internal sealed record CheckVectorStoreRequest(string StoreName);
 
-    private sealed record InsertEmbeddingRequest(string StoreName, IReadOnlyList<VectorStoragePoint> Points);
+    internal sealed record InsertEmbeddingRequest(string StoreName, IReadOnlyList<VectorStoragePoint> Points);
 
     /// <param name="PointIds">The only points the search may return, or null for the whole store.</param>
-    private sealed record SearchEmbeddingRequest(string StoreName, IReadOnlyList<float> Vector, int MaxMatches, IReadOnlyList<string>? PointIds, IReadOnlyList<HiddenChunks> HiddenChunks);
+    internal sealed record SearchEmbeddingRequest(string StoreName, IReadOnlyList<float> Vector, int MaxMatches, IReadOnlyList<string>? PointIds, IReadOnlyList<HiddenChunks> HiddenChunks);
 
-    private sealed record RetrieveVectorsRequest(string StoreName, IReadOnlyList<string> PointIds);
+    internal sealed record RetrieveVectorsRequest(string StoreName, IReadOnlyList<string> PointIds);
 
-    private sealed record DeleteEmbeddingByFileRequest(string StoreName, string FilePath, string ParentFileId, IReadOnlyCollection<string> KeepPointIds);
+    internal sealed record DeleteEmbeddingByFileRequest(string StoreName, string FilePath, string ParentFileId, IReadOnlyCollection<string> KeepPointIds);
 
-    private sealed record RelocateEmbeddingFileRequest(string StoreName, string ParentFileId, string AbsolutePath, string FileName, string RelativePath, string Fingerprint);
+    internal sealed record RelocateEmbeddingFileRequest(string StoreName, string ParentFileId, string AbsolutePath, string FileName, string RelativePath, string Fingerprint);
 
-    private sealed record OptimizeVectorStoreRequest(string StoreName);
-    
-    private sealed record DeleteVectorStoreRequest(string StoreName);
+    internal sealed record OptimizeVectorStoreRequest(string StoreName);
+
+    internal sealed record DeleteVectorStoreRequest(string StoreName);
 
     /// <summary>
     /// Preparing a backup needs nothing but the request itself.
     /// </summary>
-    private sealed record PrepareBackupRequest;
+    internal sealed record PrepareBackupRequest;
 
-    private sealed record CopyStoreForBackupRequest(string BackupId, string StoreName);
-    // ReSharper restore NotAccessedPositionalProperty.Local
+    internal sealed record CopyStoreForBackupRequest(string BackupId, string StoreName);
+    // ReSharper restore NotAccessedPositionalProperty.Global
 }

app/MindWork AI Studio/Tools/ERIClient/ERIClientBase.cs

@@ -9,7 +9,7 @@ public abstract class ERIClientBase(IERIDataSource dataSource) : IDisposable
 {
     protected readonly IERIDataSource DataSource = dataSource;
     
-    protected static readonly JsonSerializerOptions JSON_OPTIONS = new()
+    internal static readonly JsonSerializerOptions JSON_OPTIONS = new()
     {
         WriteIndented = true,
         AllowTrailingCommas = true,

app/MindWork AI Studio/Tools/Services/RustService.APIKeys.cs

@@ -63,7 +63,7 @@ public sealed partial class RustService
     private async Task<RequestedSecret> GetAPIKeyByKey(string secretKey, bool isTrying)
     {
         var secretRequest = new SelectSecretRequest(secretKey, Environment.UserName, isTrying);
-        var result = await this.http.PostAsJsonAsync("/secrets/get", secretRequest, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/get", secretRequest, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             if(!isTrying)
@@ -71,7 +71,7 @@ public sealed partial class RustService
             return new RequestedSecret(false, new EncryptedText(string.Empty), TB("Failed to get the API key due to an API issue."));
         }
 
-        var secret = await result.Content.ReadFromJsonAsync<RequestedSecret>(this.jsonRustSerializerOptions);
+        var secret = await result.Content.ReadFromJsonAsync<RequestedSecret>(JSON_OPTIONS);
         if (secret.Success)
             this.logger!.LogDebug($"Successfully retrieved the API key for '{secretKey}'.");
         else if (isTrying)
@@ -106,14 +106,14 @@ public sealed partial class RustService
     private async Task<StoreSecretResponse> StoreEncryptedAPIKeyByKey(string secretKey, EncryptedText encryptedKey)
     {
         var request = new StoreSecretRequest(secretKey, Environment.UserName, encryptedKey);
-        var result = await this.http.PostAsJsonAsync("/secrets/store", request, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/store", request, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             this.logger!.LogError($"Failed to store the API key for '{secretKey}' due to an API issue: '{result.StatusCode}'");
             return new StoreSecretResponse(false, TB("Failed to store the API key due to an API issue."));
         }
 
-        var state = await result.Content.ReadFromJsonAsync<StoreSecretResponse>(this.jsonRustSerializerOptions);
+        var state = await result.Content.ReadFromJsonAsync<StoreSecretResponse>(JSON_OPTIONS);
         if (!state.Success)
             this.logger!.LogError($"Failed to store the API key for '{secretKey}': '{state.Issue}'");
         else
@@ -149,14 +149,14 @@ public sealed partial class RustService
     private async Task<DeleteSecretResponse> DeleteAPIKeyByKey(string secretKey, bool isTrying = false)
     {
         var request = new SelectSecretRequest(secretKey, Environment.UserName, false);
-        var result = await this.http.PostAsJsonAsync("/secrets/delete", request, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/delete", request, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             this.logger!.LogError($"Failed to delete the API key for '{secretKey}' due to an API issue: '{result.StatusCode}'");
             return new DeleteSecretResponse{Success = false, WasEntryFound = false, Issue = TB("Failed to delete the API key due to an API issue.")};
         }
 
-        var state = await result.Content.ReadFromJsonAsync<DeleteSecretResponse>(this.jsonRustSerializerOptions);
+        var state = await result.Content.ReadFromJsonAsync<DeleteSecretResponse>(JSON_OPTIONS);
         if (!state.Success && !isTrying)
             this.logger!.LogError($"Failed to delete the API key for '{secretKey}': '{state.Issue}'");
 

app/MindWork AI Studio/Tools/Services/RustService.App.cs

@@ -122,7 +122,7 @@ public sealed partial class RustService
 
     public async Task<RuntimeInfoResponse> GetRuntimeInfo()
     {
-        var response = await this.http.GetFromJsonAsync<RuntimeInfoResponse>("/system/runtime/info", this.jsonRustSerializerOptions);
+        var response = await this.http.GetFromJsonAsync<RuntimeInfoResponse>("/system/runtime/info", JSON_OPTIONS);
         return response;
     }
 
@@ -140,7 +140,7 @@ public sealed partial class RustService
                 return false;
             }
 
-            var result = await response.Content.ReadFromJsonAsync<AppExitResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<AppExitResponse>(JSON_OPTIONS);
             if (result is null || !result.Success)
             {
                 this.logger?.LogError("Failed to exit the app: {Error}", result?.ErrorMessage ?? "Unknown error");
@@ -177,7 +177,7 @@ public sealed partial class RustService
                 return false;
             }
 
-            var result = await response.Content.ReadFromJsonAsync<AppRestartResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<AppRestartResponse>(JSON_OPTIONS);
             if (result is null || !result.Success)
             {
                 this.logger?.LogError("Failed to restart the app: {Error}", result?.ErrorMessage ?? "Unknown error");
@@ -203,7 +203,7 @@ public sealed partial class RustService
     {
         try
         {
-            var response = await this.http.PostAsJsonAsync("/app/interface-size", request, this.jsonRustSerializerOptions);
+            var response = await this.http.PostAsJsonAsync("/app/interface-size", request, JSON_OPTIONS);
             var result = await this.ReadInterfaceSizeResponse(response, "set the interface size");
             if (result is not null)
                 this.logger?.LogInformation("Set the interface sizes of {ScreenCount} screens. AI Studio shows with the size '{Size}' at {CurrentPercent} % and a zoom of {Zoom:0.###} on the screen '{ScreenKey}'.", request.Screens.Count, result.Size, result.CurrentPercent, result.Zoom, result.ScreenKey);
@@ -243,7 +243,7 @@ public sealed partial class RustService
             return null;
         }
 
-        var result = await response.Content.ReadFromJsonAsync<InterfaceSizeResponse>(this.jsonRustSerializerOptions);
+        var result = await response.Content.ReadFromJsonAsync<InterfaceSizeResponse>(JSON_OPTIONS);
         if (result is null || !result.Success)
         {
             this.logger?.LogError("Failed to {Action}: {Error}", action, result?.ErrorMessage ?? "Unknown error");

app/MindWork AI Studio/Tools/Services/RustService.Clipboard.cs

@@ -28,7 +28,7 @@ public sealed partial class RustService
                 return;
             }
 
-            var state = await response.Content.ReadFromJsonAsync<SetClipboardResponse>(this.jsonRustSerializerOptions);
+            var state = await response.Content.ReadFromJsonAsync<SetClipboardResponse>(JSON_OPTIONS);
             if (!state.Success)
             {
                 this.logger!.LogError("Failed to copy the text to the clipboard.");

app/MindWork AI Studio/Tools/Services/RustService.Databases.cs

@@ -24,7 +24,7 @@ public sealed partial class RustService
             using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
             cts.CancelAfter(TimeSpan.FromSeconds(45));
 
-            var databaseInfo = await this.http.GetFromJsonAsync<TDatabaseInfo>(infoPath, this.jsonRustSerializerOptions, cts.Token);
+            var databaseInfo = await this.http.GetFromJsonAsync<TDatabaseInfo>(infoPath, JSON_OPTIONS, cts.Token);
             return databaseInfo ?? unavailableFactory("The database information response was empty.");
         }
         catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
@@ -52,10 +52,10 @@ public sealed partial class RustService
         using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
         cts.CancelAfter(TimeSpan.FromMinutes(5));
 
-        using var response = await this.http.PostAsJsonAsync(path, request, this.jsonRustSerializerOptions, cts.Token);
+        using var response = await this.http.PostAsJsonAsync(path, request, JSON_OPTIONS, cts.Token);
         response.EnsureSuccessStatusCode();
 
-        var operation = await response.Content.ReadFromJsonAsync<DatabaseOperationResponse>(this.jsonRustSerializerOptions, cts.Token);
+        var operation = await response.Content.ReadFromJsonAsync<DatabaseOperationResponse>(JSON_OPTIONS, cts.Token);
         if (operation is not { Success: true })
             throw CreateDatabaseException(operation?.Issue, operation?.IssueCode, $"The {databaseName} operation failed.");
     }
@@ -65,10 +65,10 @@ public sealed partial class RustService
         using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
         cts.CancelAfter(TimeSpan.FromMinutes(5));
 
-        using var response = await this.http.PostAsJsonAsync(path, request, this.jsonRustSerializerOptions, cts.Token);
+        using var response = await this.http.PostAsJsonAsync(path, request, JSON_OPTIONS, cts.Token);
         response.EnsureSuccessStatusCode();
 
-        var operation = await response.Content.ReadFromJsonAsync<DatabaseQueryResponse<TResult>>(this.jsonRustSerializerOptions, cts.Token);
+        var operation = await response.Content.ReadFromJsonAsync<DatabaseQueryResponse<TResult>>(JSON_OPTIONS, cts.Token);
         if (operation is not { Success: true })
             throw CreateDatabaseException(operation?.Issue, operation?.IssueCode, $"The {databaseName} query failed.");
 
@@ -94,7 +94,10 @@ public sealed partial class RustService
         };
     }
 
-    private sealed record DatabaseOperationResponse(bool Success, string Issue, string IssueCode);
+    //
+    // Internal rather than private, so that the JSON context of the runtime can name them:
+    //
+    internal sealed record DatabaseOperationResponse(bool Success, string Issue, string IssueCode);
 
-    private sealed record DatabaseQueryResponse<TResult>(bool Success, string Issue, string IssueCode, TResult? Data);
+    internal sealed record DatabaseQueryResponse<TResult>(bool Success, string Issue, string IssueCode, TResult? Data);
 }

app/MindWork AI Studio/Tools/Services/RustService.Enterprise.cs

@@ -39,7 +39,7 @@ public sealed partial class RustService
             throw new HttpRequestException($"Failed to query the enterprise configurations: '{result.StatusCode}'");
         }
 
-        var configs = await result.Content.ReadFromJsonAsync<List<EnterpriseConfig>>(this.jsonRustSerializerOptions);
+        var configs = await result.Content.ReadFromJsonAsync<List<EnterpriseConfig>>(JSON_OPTIONS);
         if (configs is null)
             throw new InvalidOperationException("Failed to parse the enterprise configurations from Rust.");
 

app/MindWork AI Studio/Tools/Services/RustService.Events.cs

@@ -35,7 +35,7 @@ public partial class RustService
                             continue;
                         
                         // Deserialize the Tauri event:
-                        var tauriEvent = JsonSerializer.Deserialize<TauriEvent>(line, this.jsonRustSerializerOptions);
+                        var tauriEvent = JsonSerializer.Deserialize<TauriEvent>(line, JSON_OPTIONS);
                         
                         // Forward relevant events to the message bus:
                         if (tauriEvent != default && tauriEvent.EventType

app/MindWork AI Studio/Tools/Services/RustService.FileSystem.cs

@@ -16,10 +16,10 @@ public sealed partial class RustService
                 var startDirectory = initialDirectory is null ? null : PathTools.FindNearestExistingPath(initialDirectory);
                 var result = startDirectory is null
                     ? await this.http.PostAsync($"/select/directory?title={encodedTitle}", null)
-                    : await this.http.PostAsJsonAsync($"/select/directory?title={encodedTitle}", new PreviousDirectory(startDirectory), this.jsonRustSerializerOptions);
+                    : await this.http.PostAsJsonAsync($"/select/directory?title={encodedTitle}", new PreviousDirectory(startDirectory), JSON_OPTIONS);
 
                 if (result.IsSuccessStatusCode)
-                    return await result.Content.ReadFromJsonAsync<DirectorySelectionResponse>(this.jsonRustSerializerOptions);
+                    return await result.Content.ReadFromJsonAsync<DirectorySelectionResponse>(JSON_OPTIONS);
 
                 this.logger!.LogError("Failed to select a directory: '{StatusCode}'", result.StatusCode);
                 return new DirectorySelectionResponse(true, string.Empty);
@@ -63,9 +63,9 @@ public sealed partial class RustService
                     Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
-                var result = await this.http.PostAsJsonAsync("/select/file", payload, this.jsonRustSerializerOptions);
+                var result = await this.http.PostAsJsonAsync("/select/file", payload, JSON_OPTIONS);
                 if (result.IsSuccessStatusCode)
-                    return await result.Content.ReadFromJsonAsync<FileSelectionResponse>(this.jsonRustSerializerOptions);
+                    return await result.Content.ReadFromJsonAsync<FileSelectionResponse>(JSON_OPTIONS);
 
                 this.logger!.LogError("Failed to select a file: '{StatusCode}'", result.StatusCode);
                 return new FileSelectionResponse(true, string.Empty);
@@ -87,9 +87,9 @@ public sealed partial class RustService
                     Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
-                var result = await this.http.PostAsJsonAsync("/select/files", payload, this.jsonRustSerializerOptions);
+                var result = await this.http.PostAsJsonAsync("/select/files", payload, JSON_OPTIONS);
                 if (result.IsSuccessStatusCode)
-                    return await result.Content.ReadFromJsonAsync<FilesSelectionResponse>(this.jsonRustSerializerOptions);
+                    return await result.Content.ReadFromJsonAsync<FilesSelectionResponse>(JSON_OPTIONS);
 
                 this.logger!.LogError("Failed to select files: '{StatusCode}'", result.StatusCode);
                 return new FilesSelectionResponse(true, Array.Empty<string>());
@@ -118,9 +118,9 @@ public sealed partial class RustService
                     Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
-                var result = await this.http.PostAsJsonAsync("/save/file", payload, this.jsonRustSerializerOptions);
+                var result = await this.http.PostAsJsonAsync("/save/file", payload, JSON_OPTIONS);
                 if (result.IsSuccessStatusCode)
-                    return await result.Content.ReadFromJsonAsync<FileSaveResponse>(this.jsonRustSerializerOptions);
+                    return await result.Content.ReadFromJsonAsync<FileSaveResponse>(JSON_OPTIONS);
 
                 this.logger!.LogError("Failed to select a file for writing operation: '{StatusCode}'", result.StatusCode);
                 return new FileSaveResponse(true, string.Empty);
@@ -133,7 +133,7 @@ public sealed partial class RustService
         HttpResponseMessage result;
         try
         {
-            result = await this.http.PostAsJsonAsync("/open/path", new OpenPathRequest(path), this.jsonRustSerializerOptions);
+            result = await this.http.PostAsJsonAsync("/open/path", new OpenPathRequest(path), JSON_OPTIONS);
         }
         catch (HttpRequestException e)
         {
@@ -154,7 +154,7 @@ public sealed partial class RustService
                 return new OpenPathResponse(false, string.Format(TB("The runtime file manager endpoint returned '{0}'."), result.StatusCode));
             }
 
-            var response = await result.Content.ReadFromJsonAsync<OpenPathResponse>(this.jsonRustSerializerOptions);
+            var response = await result.Content.ReadFromJsonAsync<OpenPathResponse>(JSON_OPTIONS);
             var normalizedResponse = response.Success
                 ? response
                 : new OpenPathResponse(false, string.IsNullOrWhiteSpace(response.Issue) ? TB("The runtime file manager endpoint failed without details.") : response.Issue);
@@ -187,7 +187,7 @@ public sealed partial class RustService
         HttpResponseMessage result;
         try
         {
-            result = await this.http.PostAsJsonAsync("/open/document", new OpenDocumentRequest(path, pageNumber), this.jsonRustSerializerOptions);
+            result = await this.http.PostAsJsonAsync("/open/document", new OpenDocumentRequest(path, pageNumber), JSON_OPTIONS);
         }
         catch (HttpRequestException e)
         {
@@ -208,7 +208,7 @@ public sealed partial class RustService
                 return new OpenDocumentResponse(false, false, string.Format(TB("The runtime document endpoint returned '{0}'."), result.StatusCode));
             }
 
-            var response = await result.Content.ReadFromJsonAsync<OpenDocumentResponse>(this.jsonRustSerializerOptions);
+            var response = await result.Content.ReadFromJsonAsync<OpenDocumentResponse>(JSON_OPTIONS);
             if (response.Success)
             {
                 //

app/MindWork AI Studio/Tools/Services/RustService.Image.cs

@@ -20,10 +20,10 @@ public sealed partial class RustService
         bool optimize,
         CancellationToken token = default)
     {
-        using var response = await this.http.PostAsJsonAsync("/image/prepare", new { path, optimize }, this.jsonRustSerializerOptions, token);
+        using var response = await this.http.PostAsJsonAsync("/image/prepare", new { path, optimize }, JSON_OPTIONS, token);
         response.EnsureSuccessStatusCode();
 
-        return await response.Content.ReadFromJsonAsync<ImagePrepareResponse>(this.jsonRustSerializerOptions, token)
+        return await response.Content.ReadFromJsonAsync<ImagePrepareResponse>(JSON_OPTIONS, token)
             ?? throw new InvalidDataException("The Rust image preparation returned an empty response.");
     }
 
@@ -44,10 +44,10 @@ public sealed partial class RustService
     {
         try
         {
-            using var response = await this.http.PostAsJsonAsync("/image/prepare-for-model", new { path, maxBytes }, this.jsonRustSerializerOptions, token);
+            using var response = await this.http.PostAsJsonAsync("/image/prepare-for-model", new { path, maxBytes }, JSON_OPTIONS, token);
             response.EnsureSuccessStatusCode();
 
-            return await response.Content.ReadFromJsonAsync<PreparedModelImage>(this.jsonRustSerializerOptions, token)
+            return await response.Content.ReadFromJsonAsync<PreparedModelImage>(JSON_OPTIONS, token)
                 ?? PreparedModelImage.Failed(ModelImageErrorCode.UNKNOWN);
         }
         catch (Exception e) when (e is not OperationCanceledException)

app/MindWork AI Studio/Tools/Services/RustService.Log.cs

@@ -10,7 +10,7 @@ public sealed partial class RustService
     /// <returns>The paths of the log files.</returns>
     public async Task<GetLogPathsResponse> GetLogPaths()
     {
-        return await this.http.GetFromJsonAsync<GetLogPathsResponse>("/log/paths", this.jsonRustSerializerOptions);
+        return await this.http.GetFromJsonAsync<GetLogPathsResponse>("/log/paths", JSON_OPTIONS);
     }
 
     /// <summary>
@@ -33,7 +33,7 @@ public sealed partial class RustService
             // feed itself. The unobserved task exception handler in Program.cs remains the safety net here.
             //
             var request = new LogEventRequest(timestamp, level, category, message, exception, stackTrace);
-            _ = this.http.PostAsJsonAsync("/log/event", request, this.jsonRustSerializerOptions);
+            _ = this.http.PostAsJsonAsync("/log/event", request, JSON_OPTIONS);
         }
         catch
         {

app/MindWork AI Studio/Tools/Services/RustService.Media.cs

@@ -18,11 +18,11 @@ public partial class RustService
         using var response = await this.http.PostAsJsonAsync(
             "/media/jobs",
             new CreateMediaJobRequest(inputPath, outputPath, OpusBitrateBps: opusBitrateBps),
-            this.jsonRustSerializerOptions,
+            JSON_OPTIONS,
             token);
 
         response.EnsureSuccessStatusCode();
-        var result = await response.Content.ReadFromJsonAsync<CreateMediaJobResponse>(this.jsonRustSerializerOptions, token);
+        var result = await response.Content.ReadFromJsonAsync<CreateMediaJobResponse>(JSON_OPTIONS, token);
         return result?.JobId ?? throw new InvalidOperationException("The Rust runtime did not return a media job ID.");
     }
 
@@ -49,7 +49,7 @@ public partial class RustService
                 continue;
 
             var json = line["data:".Length..].Trim();
-            var mediaEvent = JsonSerializer.Deserialize<MediaJobEvent>(json, this.jsonRustSerializerOptions);
+            var mediaEvent = JsonSerializer.Deserialize<MediaJobEvent>(json, JSON_OPTIONS);
             if (mediaEvent is not null)
                 yield return mediaEvent;
 

app/MindWork AI Studio/Tools/Services/RustService.Secrets.cs

@@ -65,14 +65,14 @@ public sealed partial class RustService
         var secretKey = SecretKey(secretId, storeType);
         var encryptedSecret = await this.encryptor!.Encrypt(secretData);
         var request = new StoreSecretRequest(secretKey, Environment.UserName, encryptedSecret);
-        var result = await this.http.PostAsJsonAsync("/secrets/store", request, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/store", request, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             this.logger!.LogError($"Failed to store the secret data for '{secretKey}' due to an API issue: '{result.StatusCode}'");
             return new StoreSecretResponse(false, TB("Failed to store the secret data due to an API issue."));
         }
         
-        var state = await result.Content.ReadFromJsonAsync<StoreSecretResponse>(this.jsonRustSerializerOptions);
+        var state = await result.Content.ReadFromJsonAsync<StoreSecretResponse>(JSON_OPTIONS);
         if (!state.Success)
             this.logger!.LogError($"Failed to store the secret data for '{secretKey}': '{state.Issue}'");
 
@@ -104,7 +104,7 @@ public sealed partial class RustService
     private async Task<RequestedSecret> GetSecretByKey(string secretKey, bool isTrying)
     {
         var secretRequest = new SelectSecretRequest(secretKey, Environment.UserName, isTrying);
-        var result = await this.http.PostAsJsonAsync("/secrets/get", secretRequest, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/get", secretRequest, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             if(isTrying)
@@ -114,7 +114,7 @@ public sealed partial class RustService
             return new RequestedSecret(false, new EncryptedText(string.Empty), TB("Failed to get the secret data due to an API issue."));
         }
 
-        var state = await result.Content.ReadFromJsonAsync<RequestedSecret>(this.jsonRustSerializerOptions);
+        var state = await result.Content.ReadFromJsonAsync<RequestedSecret>(JSON_OPTIONS);
         if (!state.Success)
         {
             //
@@ -138,14 +138,14 @@ public sealed partial class RustService
     private async Task<DeleteSecretResponse> DeleteSecretByKey(string secretKey)
     {
         var request = new SelectSecretRequest(secretKey, Environment.UserName, false);
-        var result = await this.http.PostAsJsonAsync("/secrets/delete", request, this.jsonRustSerializerOptions);
+        var result = await this.http.PostAsJsonAsync("/secrets/delete", request, JSON_OPTIONS);
         if (!result.IsSuccessStatusCode)
         {
             this.logger!.LogError($"Failed to delete the secret data for '{secretKey}' due to an API issue: '{result.StatusCode}'");
             return new DeleteSecretResponse{Success = false, WasEntryFound = false, Issue = TB("Failed to delete the secret data due to an API issue.")};
         }
         
-        var state = await result.Content.ReadFromJsonAsync<DeleteSecretResponse>(this.jsonRustSerializerOptions);
+        var state = await result.Content.ReadFromJsonAsync<DeleteSecretResponse>(JSON_OPTIONS);
         if (!state.Success)
             this.logger!.LogError($"Failed to delete the secret data for '{secretKey}': '{state.Issue}'");
         

app/MindWork AI Studio/Tools/Services/RustService.Share.cs

@@ -1,4 +1,4 @@
-// ReSharper disable NotAccessedPositionalProperty.Local
+// ReSharper disable NotAccessedPositionalProperty.Global
 using AIStudio.Tools.Rust;
 
 namespace AIStudio.Tools.Services;
@@ -14,14 +14,14 @@ public sealed partial class RustService
     {
         try
         {
-            using var response = await this.http.PostAsJsonAsync("/share/file", new ShareFileRequest(filePath), this.jsonRustSerializerOptions);
+            using var response = await this.http.PostAsJsonAsync("/share/file", new ShareFileRequest(filePath), JSON_OPTIONS);
             if (!response.IsSuccessStatusCode)
             {
                 this.logger?.LogError($"The Rust runtime rejected the share request: {response.StatusCode}.");
                 return new(ShareSheetOutcome.FAILED, $"The Rust runtime rejected the share request: {response.StatusCode}.");
             }
 
-            var result = await response.Content.ReadFromJsonAsync<ShareFileResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<ShareFileResponse>(JSON_OPTIONS);
             if (result is null)
             {
                 this.logger?.LogError("The Rust runtime answered the share request without a result.");
@@ -50,5 +50,8 @@ public sealed partial class RustService
         }
     }
 
-    private sealed record ShareFileRequest(string FilePath);
+    /// <remarks>
+    /// Internal rather than private, so that the JSON context of the runtime can name it.
+    /// </remarks>
+    internal sealed record ShareFileRequest(string FilePath);
 }

app/MindWork AI Studio/Tools/Services/RustService.Shortcuts.cs

@@ -18,7 +18,7 @@ public sealed partial class RustService
         try
         {
             var request = new RegisterShortcutRequest(shortcutId, shortcut, description, reconfigure);
-            var response = await this.http.PostAsJsonAsync("/shortcuts/register", request, this.jsonRustSerializerOptions);
+            var response = await this.http.PostAsJsonAsync("/shortcuts/register", request, JSON_OPTIONS);
 
             if (!response.IsSuccessStatusCode)
             {
@@ -26,7 +26,7 @@ public sealed partial class RustService
                 return ShortcutRegistrationResult.Failed(TB("The global shortcut could not be registered because the desktop service is unavailable."));
             }
 
-            var result = await response.Content.ReadFromJsonAsync<ShortcutRegistrationResult>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<ShortcutRegistrationResult>(JSON_OPTIONS);
             if (result is null || !result.Success)
             {
                 this.logger?.LogError("Failed to register global shortcut '{ShortcutId}': {Error}", shortcutId, result?.ErrorMessage ?? "Unknown error");
@@ -53,7 +53,7 @@ public sealed partial class RustService
         try
         {
             var request = new ValidateShortcutRequest(shortcut);
-            var response = await this.http.PostAsJsonAsync("/shortcuts/validate", request, this.jsonRustSerializerOptions);
+            var response = await this.http.PostAsJsonAsync("/shortcuts/validate", request, JSON_OPTIONS);
 
             if (!response.IsSuccessStatusCode)
             {
@@ -61,7 +61,7 @@ public sealed partial class RustService
                 return new ShortcutValidationResult(false, "Network error during validation", false, string.Empty);
             }
 
-            var result = await response.Content.ReadFromJsonAsync<ShortcutValidationResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<ShortcutValidationResponse>(JSON_OPTIONS);
             if (result is null)
                 return new ShortcutValidationResult(false, "Invalid response from server", false, string.Empty);
 
@@ -91,7 +91,7 @@ public sealed partial class RustService
                 return false;
             }
 
-            var result = await response.Content.ReadFromJsonAsync<ShortcutResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<ShortcutResponse>(JSON_OPTIONS);
             if (result is null || !result.Success)
             {
                 this.logger?.LogError("Failed to suspend shortcut processing: {Error}", result?.ErrorMessage ?? "Unknown error");
@@ -123,7 +123,7 @@ public sealed partial class RustService
                 return false;
             }
 
-            var result = await response.Content.ReadFromJsonAsync<ShortcutResponse>(this.jsonRustSerializerOptions);
+            var result = await response.Content.ReadFromJsonAsync<ShortcutResponse>(JSON_OPTIONS);
             if (result is null || !result.Success)
             {
                 this.logger?.LogError("Failed to resume shortcut processing: {Error}", result?.ErrorMessage ?? "Unknown error");

app/MindWork AI Studio/Tools/Services/RustService.Tokenizer.cs

@@ -17,7 +17,7 @@ public sealed partial class RustService : ITokenizerStorage
     {
         var result = await this.http.PostAsJsonAsync("/tokenizer/validate", new {
             file_path = filePath,
-        }, this.jsonRustSerializerOptions);
+        }, JSON_OPTIONS);
 
         if (!result.IsSuccessStatusCode)
         {
@@ -25,7 +25,7 @@ public sealed partial class RustService : ITokenizerStorage
             return CreateUnavailableTokenizerResponse("An error occured while sending the path to the Rust framework for validation: "+result.StatusCode);
         }
 
-        var response = await result.Content.ReadFromJsonAsync<TokenizerResponse>(this.jsonRustSerializerOptions);
+        var response = await result.Content.ReadFromJsonAsync<TokenizerResponse>(JSON_OPTIONS);
 
         return response;
     }
@@ -36,7 +36,7 @@ public sealed partial class RustService : ITokenizerStorage
         var result = await this.http.PostAsJsonAsync("/tokenizer/store", new {
             model_id = modelId,
             file_path = filePath,
-        }, this.jsonRustSerializerOptions);
+        }, JSON_OPTIONS);
 
         if (!result.IsSuccessStatusCode)
         {
@@ -44,7 +44,7 @@ public sealed partial class RustService : ITokenizerStorage
             return CreateUnavailableTokenizerResponse("An error occured while sending the path to the Rust framework for storing: "+result.StatusCode);
         }
 
-        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(this.jsonRustSerializerOptions);
+        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(JSON_OPTIONS);
     }
 
     public async Task<TokenizerResponse> DeleteTokenizer(string modelId)
@@ -52,7 +52,7 @@ public sealed partial class RustService : ITokenizerStorage
         this.logger!.LogInformation($"Deleting tokenizer for model '{modelId}'");
         var result = await this.http.PostAsJsonAsync("/tokenizer/delete", new {
             model_id = modelId,
-        }, this.jsonRustSerializerOptions);
+        }, JSON_OPTIONS);
 
         if (!result.IsSuccessStatusCode)
         {
@@ -60,7 +60,7 @@ public sealed partial class RustService : ITokenizerStorage
             return CreateUnavailableTokenizerResponse("An error occured while sending the tokenizer delete request to the Rust framework: "+result.StatusCode);
         }
 
-        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(this.jsonRustSerializerOptions);
+        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(JSON_OPTIONS);
     }
     
     public Task<TokenizerResponse?> GetTokenCount(AIStudio.Settings.Provider provider, string text, CancellationToken cancellationToken = default) =>
@@ -74,7 +74,7 @@ public sealed partial class RustService : ITokenizerStorage
         var result = await this.http.PostAsJsonAsync("/tokenizer/count", new {
             text,
             tokenizer_path = tokenizerPath,
-        }, this.jsonRustSerializerOptions, cancellationToken);
+        }, JSON_OPTIONS, cancellationToken);
 
         if (!result.IsSuccessStatusCode)
         {
@@ -82,6 +82,6 @@ public sealed partial class RustService : ITokenizerStorage
             return CreateUnavailableTokenizerResponse("Error while getting token count from Rust service: "+result.StatusCode);
         }
 
-        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(this.jsonRustSerializerOptions, cancellationToken);
+        return await result.Content.ReadFromJsonAsync<TokenizerResponse>(JSON_OPTIONS, cancellationToken);
     }
 }

app/MindWork AI Studio/Tools/Services/RustService.Updates.cs

@@ -9,7 +9,7 @@ public sealed partial class RustService
         try
         {
             var cts = new CancellationTokenSource(TimeSpan.FromSeconds(45));
-            var response = await this.http.GetFromJsonAsync<UpdateResponse>("/updates/check", this.jsonRustSerializerOptions, cts.Token);
+            var response = await this.http.GetFromJsonAsync<UpdateResponse>("/updates/check", JSON_OPTIONS, cts.Token);
             
             if (response == default)
             {

app/MindWork AI Studio/Tools/Services/RustService.cs

@@ -34,7 +34,10 @@ public sealed partial class RustService : BackgroundService
     private readonly SemaphoreSlim userLanguageLock = new(1, 1);
     private readonly SemaphoreSlim userNameLock = new(1, 1);
 
-    private readonly JsonSerializerOptions jsonRustSerializerOptions = new()
+    /// <summary>
+    /// The JSON options of nearly every call to the runtime, which names its fields in snake case.
+    /// </summary>
+    internal static readonly JsonSerializerOptions JSON_OPTIONS = new()
     {
         PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
         Converters =

app/Tests/Serialization/Fixtures/anthropic-messages-request.json

@@ -0,0 +1 @@
+{"model":"messages-model","messages":[{"content":"What is the weather?","role":"user"},{"content":[{"type":"text","text":"Compare these pictures."},{"type":"image","source":{"type":"base64","media_type":"image/png","data":"iVBORw0KGgo="}},{"type":"image","source":{"type":"url","url":"https://example.org/picture.png"}}],"role":"user"},{"content":[{"type":"text","text":"Let me search."},{"type":"tool_use","id":"toolu_1","name":"web_search","input":{"query":"weather"}}],"role":"assistant"},{"content":[{"type":"tool_result","tool_use_id":"toolu_1","content":"It is sunny.","is_error":true}],"role":"user"}],"max_tokens":1024,"stream":true,"system":"You answer briefly.","tools":[{"name":"web_search","description":"Search the web.","strict":true,"input_schema":{"type":"object","properties":{"query":{"type":"string","description":"The search query."},"page":{"type":"integer","description":"The page, starting at 1."}},"required":["query"],"additionalProperties":false}}],"temperature":0.5,"top_k":40,"seed":12345678901,"stop":["END",7],"reasoning":{"effort":"low","summary":""},"logprobs":false}

app/Tests/Serialization/Fixtures/chat-completion-request.json

@@ -0,0 +1 @@
+{"model":"chat-model","messages":[{"content":"You answer briefly.","role":"system"},{"content":[{"type":"text","text":"What do the pictures show?"},{"type":"image_url","image_url":{"url":"data:image/png;base64,iVBORw0KGgo="}},{"type":"image_url","image_url":"https://example.org/picture.png"}],"role":"user"},{"role":"assistant","content":null,"reasoning_content":"The weather needs a search.","tool_calls":[{"id":"call_1","type":"function","function":{"name":"web_search","arguments":"{\u0022query\u0022:\u0022weather\u0022}"},"index":0}]},{"role":"tool","content":"It is sunny.","tool_call_id":"call_1"}],"stream":true,"tools":[{"type":"function","function":{"name":"web_search","description":"Search the web.","parameters":{"type":"object","properties":{"query":{"type":"string","description":"The search query."},"page":{"type":["integer","null"],"description":"The page, starting at 1."}},"required":["query","page"],"additionalProperties":false},"strict":true}}],"parallel_tool_calls":false,"stream_options":{"include_usage":true},"temperature":0.5,"top_k":40,"seed":12345678901,"stop":["END",7],"reasoning":{"effort":"low","summary":""},"logprobs":false}

app/Tests/Serialization/Fixtures/responses-request.json

@@ -0,0 +1 @@
+{"model":"responses-model","input":[{"content":"You answer briefly.","role":"developer"},{"content":[{"type":"input_text","text":"What does the picture show?"},{"type":"input_image","image_url":"data:image/png;base64,iVBORw0KGgo="}],"role":"user"},{"type":"function_call","id":"fc_1","call_id":"call_1","name":"web_search","arguments":"{\u0022query\u0022:\u0022weather\u0022}"},{"type":"function_call_output","call_id":"call_1","output":"It is sunny."}],"stream":true,"store":false,"tools":[{"type":"function","name":"web_search","description":"Search the web.","parameters":{"type":"object","properties":{"query":{"type":"string","description":"The search query."},"page":{"type":["integer","null"],"description":"The page, starting at 1."}},"required":["query","page"],"additionalProperties":false},"strict":true}],"temperature":0.5,"top_k":40,"seed":12345678901,"stop":["END",7],"reasoning":{"effort":"low","summary":""},"logprobs":false}

app/Tests/Serialization/JsonContractTests.cs

@@ -12,6 +12,12 @@ namespace AIStudio.Tests.Serialization;
 public sealed class JsonContractTests
 {
     [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.Stored))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ProviderRequests))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ProviderAnswers))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.RuntimeRequests))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.RuntimeAnswers))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ServiceRequests))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ServiceAnswers))]
     public void TheContractsMatchThoseOfReflection(JsonTestRoot root)
     {
         var baseline = JsonReflectionBaseline.Of(root.Options);

app/Tests/Serialization/JsonDefaultsTests.cs

@@ -7,11 +7,12 @@ namespace AIStudio.Tests.Serialization;
 /// Checks that a property missing in the JSON keeps the value a new object starts with.
 /// </summary>
 /// <remarks>
-/// Files written by an older version of AI Studio lack every property added since. Reading them has to give
-/// those properties their defaults, as a new object has them, e.g., a sub-object of the settings instead of
-/// null. Source generation in .NET 10 breaks this for init-only properties: it sets them all while creating
-/// the object, and a property missing in the JSON gets the default of its type instead (dotnet/runtime#84484).
-/// Hence, the types AI Studio stores use set instead of init.<br/><br/>
+/// Files written by an older version of AI Studio lack every property added since, and an answer of a
+/// provider, of the runtime, or of a service leaves out whatever it has nothing to say about. Reading them has
+/// to give those properties their defaults, as a new object has them, e.g., a sub-object of the settings
+/// instead of null. Source generation in .NET 10 breaks this for init-only properties: it sets them all while
+/// creating the object, and a property missing in the JSON gets the default of its type instead
+/// (dotnet/runtime#84484). Hence, the types AI Studio reads use set instead of init.<br/><br/>
 ///
 /// A new object is created the way reflection creates it: with its parameterless constructor, or, for a
 /// struct, as the default of the struct. Source generation passes the values of a positional record struct
@@ -21,6 +22,9 @@ namespace AIStudio.Tests.Serialization;
 public sealed class JsonDefaultsTests
 {
     [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.Stored))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ProviderAnswers))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.RuntimeAnswers))]
+    [TestCaseSource(typeof(JsonTestRoots), nameof(JsonTestRoots.ServiceAnswers))]
     public void AnEmptyObjectGetsTheDefaultsOfANewOne(JsonTestRoot root)
     {
         var baseline = JsonReflectionBaseline.Of(root.Options);
@@ -60,7 +64,14 @@ public sealed class JsonDefaultsTests
         Assert.That(failures, Is.Empty);
     }
 
-    private static string ValueAsJson(JsonPropertyInfo property, object instance, JsonSerializerOptions options) => JsonSerializer.Serialize(property.Get!(instance), property.PropertyType, options);
+    private static string ValueAsJson(JsonPropertyInfo property, object instance, JsonSerializerOptions options) => AsJson(property.Get!(instance), property.PropertyType, options);
 
-    private static string DefaultAsJson(Type type, JsonSerializerOptions options) => type.IsValueType ? JsonSerializer.Serialize(Activator.CreateInstance(type), type, options) : "null";
+    private static string DefaultAsJson(Type type, JsonSerializerOptions options) => type.IsValueType ? AsJson(Activator.CreateInstance(type), type, options) : "null";
+
+    private static string AsJson(object? value, Type type, JsonSerializerOptions options) => value switch
+    {
+        // The default of a JsonElement holds no JSON at all, so it cannot be written:
+        JsonElement { ValueKind: JsonValueKind.Undefined } => "no JSON",
+        _ => JsonSerializer.Serialize(value, type, options),
+    };
 }

app/Tests/Serialization/JsonGoldenFileTests.cs

@@ -85,5 +85,5 @@ public sealed class JsonGoldenFileTests
     /// <remarks>
     /// Read from the source tree, the way the other fixtures are, so the file needs no entry in the project file.
     /// </remarks>
-    private static string ReadFixture(string fileName, [CallerFilePath] string sourceFilePath = "") => File.ReadAllText(Path.Combine(Path.GetDirectoryName(sourceFilePath)!, "Fixtures", fileName));
+    internal static string ReadFixture(string fileName, [CallerFilePath] string sourceFilePath = "") => File.ReadAllText(Path.Combine(Path.GetDirectoryName(sourceFilePath)!, "Fixtures", fileName));
 }

app/Tests/Serialization/JsonGoldenRequest.cs

@@ -0,0 +1,15 @@
+using System.Text.Json;
+
+namespace AIStudio.Tests.Serialization;
+
+/// <summary>
+/// A request in the fixtures, together with how AI Studio builds it and the options it writes it with.
+/// </summary>
+/// <param name="FileName">The name of the file in the folder Fixtures next to the tests, which holds the request as it got sent before.</param>
+/// <param name="Create">Builds the request the way AI Studio does.</param>
+/// <param name="Options">The options AI Studio writes the request with.</param>
+public sealed record JsonGoldenRequest(string FileName, Func<object> Create, JsonSerializerOptions Options)
+{
+    /// <inheritdoc />
+    public override string ToString() => this.FileName;
+}

app/Tests/Serialization/JsonGoldenRequestTests.cs

@@ -0,0 +1,33 @@
+using System.Text.Json;
+
+using AIStudio.Provider;
+
+namespace AIStudio.Tests.Serialization;
+
+/// <summary>
+/// Writes requests the way AI Studio sends them, and checks that they get sent just as before.
+/// </summary>
+/// <remarks>
+/// The files in the folder Fixtures were written with the contracts of reflection, before AI Studio got
+/// contracts of its own. A provider reads every byte of a request, and one which got written otherwise, e.g.,
+/// with a field under another name or without the tools, gets refused or misread. The requests are made up,
+/// see <see cref="JsonSampleRequests"/>.
+/// </remarks>
+[TestFixture]
+public sealed class JsonGoldenRequestTests
+{
+    private static IEnumerable<JsonGoldenRequest> GoldenRequests()
+    {
+        TestHost.PrepareStaticState();
+        yield return new("chat-completion-request.json", JsonSampleRequests.ChatCompletion, ProviderJsonOptions.OPTIONS);
+        yield return new("responses-request.json", JsonSampleRequests.Responses, ProviderJsonOptions.OPTIONS);
+        yield return new("anthropic-messages-request.json", () => JsonSampleRequests.Anthropic(), ProviderJsonOptions.OPTIONS);
+    }
+
+    [TestCaseSource(nameof(GoldenRequests))]
+    public void ARequestIsSentAsBefore(JsonGoldenRequest goldenRequest)
+    {
+        var request = goldenRequest.Create();
+        Assert.That(JsonSerializer.Serialize(request, request.GetType(), goldenRequest.Options), Is.EqualTo(JsonGoldenFileTests.ReadFixture(goldenRequest.FileName)));
+    }
+}

app/Tests/Serialization/JsonSampleRequests.cs

@@ -0,0 +1,143 @@
+using System.Text.Json;
+
+using AIStudio.Provider;
+using AIStudio.Provider.Anthropic;
+using AIStudio.Provider.OpenAI;
+using AIStudio.Tools.ToolCallingSystem;
+
+using AnthropicImageUrl = AIStudio.Provider.Anthropic.SubContentImageUrl;
+using OpenAIImageUrl = AIStudio.Provider.OpenAI.SubContentImageUrl;
+
+namespace AIStudio.Tests.Serialization;
+
+/// <summary>
+/// Requests to LLM providers as AI Studio builds them, with every kind of content they carry.
+/// </summary>
+/// <remarks>
+/// The values are made up. What counts is that every part of a request holds one, so that its golden file shows
+/// how each part gets written.
+/// </remarks>
+public static class JsonSampleRequests
+{
+    /// <summary>
+    /// A tool with one required and one optional argument, the shape the web search has.
+    /// </summary>
+    public static ToolDefinition Tool() => new()
+    {
+        Id = "web_search",
+        Function = new()
+        {
+            Name = "web_search",
+            DescriptionForLLM = "Search the web.",
+            Strict = true,
+            Parameters = ToolParameterSchemaBuilder.Create()
+                .RequiredString("query", "The search query.")
+                .OptionalInteger("page", "The page, starting at 1.")
+                .Build(),
+        },
+    };
+
+    /// <summary>
+    /// A request to a Chat Completions API, with a tool, a call of it, and its result.
+    /// </summary>
+    public static ChatCompletionAPIRequest ChatCompletion() => new("chat-model", Messages(), true)
+    {
+        Tools = [ProviderToolAdapters.ToChatCompletionTool(Tool(), hostEnforcesStrict: true)],
+        ParallelToolCalls = false,
+        AdditionalApiParameters = ApiParameters(),
+    };
+
+    /// <summary>
+    /// A request to the Responses API of OpenAI, with an item of an earlier answer and the result of a tool.
+    /// </summary>
+    public static ResponsesAPIRequest Responses() => new("responses-model",
+        [
+            new TextMessage("You answer briefly.", "developer"),
+            new MultimodalMessage(
+            [
+                new SubContentInputText(SubContentType.INPUT_TEXT, "What does the picture show?"),
+                new SubContentInputImage(SubContentType.INPUT_IMAGE, "data:image/png;base64,iVBORw0KGgo="),
+            ], "user"),
+            Parse("""{"type":"function_call","id":"fc_1","call_id":"call_1","name":"web_search","arguments":"{\"query\":\"weather\"}"}"""),
+            new ResponsesFunctionCallOutputItem { CallId = "call_1", Output = "It is sunny." },
+        ],
+        true, false, [ProviderToolAdapters.ToResponsesTool(Tool())])
+    {
+        AdditionalApiParameters = ApiParameters(),
+    };
+
+    /// <summary>
+    /// A request to the Messages API of Anthropic, with images from a URL and as data, and a tool round.
+    /// </summary>
+    public static ChatRequest Anthropic() => new("messages-model",
+        [
+            new TextMessage("What is the weather?", "user"),
+            new MultimodalMessage(
+            [
+                new SubContentText(SubContentType.TEXT, "Compare these pictures."),
+                new SubContentImage(SubContentType.IMAGE, new SubContentBase64Image { MediaType = "image/png", Data = "iVBORw0KGgo=" }),
+                new SubContentImage(SubContentType.IMAGE, new AnthropicImageUrl { Url = "https://example.org/picture.png" }),
+            ], "user"),
+            new AnthropicMessage(
+            [
+                Parse("""{"type":"text","text":"Let me search."}"""),
+                Parse("""{"type":"tool_use","id":"toolu_1","name":"web_search","input":{"query":"weather"}}"""),
+            ]),
+            new AnthropicToolResultMessage([new AnthropicToolResultContent { ToolUseId = "toolu_1", Content = "It is sunny.", IsError = true }]),
+        ],
+        1024, true, "You answer briefly.")
+    {
+        Tools = [ProviderToolAdapters.ToAnthropicTool(Tool())],
+        AdditionalApiParameters = ApiParameters(),
+    };
+
+    private static List<IMessageBase> Messages() =>
+    [
+        new TextMessage("You answer briefly.", "system"),
+        new MultimodalMessage(
+        [
+            new SubContentText(SubContentType.TEXT, "What do the pictures show?"),
+            new SubContentImageUrlNested(SubContentType.IMAGE_URL, new SubContentImageUrlData { Url = "data:image/png;base64,iVBORw0KGgo=" }),
+            new OpenAIImageUrl(SubContentType.IMAGE_URL, "https://example.org/picture.png"),
+        ], "user"),
+        new AssistantToolCallMessage
+        {
+            Content = Parse("null"),
+            ReasoningContent = "The weather needs a search.",
+            ToolCalls =
+            [
+                new ChatCompletionToolCall
+                {
+                    Id = "call_1",
+                    Function = new() { Name = "web_search", Arguments = """{"query":"weather"}""" },
+                    AdditionalMetadata = { ["index"] = Parse("0") },
+                },
+            ],
+        },
+        new ToolResultMessage { Content = "It is sunny.", ToolCallId = "call_1" },
+    ];
+
+    /// <summary>
+    /// Additional API parameters of every kind, read the way the provider settings read them.
+    /// </summary>
+    private static IDictionary<string, object> ApiParameters()
+    {
+        if (!AdditionalApiParametersParser.TryParse("""
+                "temperature": 0.5,
+                "top_k": 40,
+                "seed": 12345678901,
+                "stop": ["END", 7],
+                "reasoning": { "effort": "low", "summary": null },
+                "logprobs": false
+                """, out var parameters, out var errorMessage))
+            throw new InvalidOperationException(errorMessage);
+
+        return parameters;
+    }
+
+    private static JsonElement Parse(string json)
+    {
+        using var document = JsonDocument.Parse(json);
+        return document.RootElement.Clone();
+    }
+}

app/Tests/Serialization/JsonTestRoots.Providers.cs

@@ -0,0 +1,94 @@
+using System.Text.Json;
+
+using AIStudio.Provider;
+using AIStudio.Provider.Anthropic;
+using AIStudio.Provider.Google;
+using AIStudio.Provider.Groq;
+using AIStudio.Provider.HuggingFace;
+using AIStudio.Provider.OpenAI;
+using AIStudio.Provider.OpenRouter;
+using AIStudio.Provider.Requesty;
+
+using AnthropicResponseStreamLine = AIStudio.Provider.Anthropic.ResponseStreamLine;
+using FireworksResponseStreamLine = AIStudio.Provider.Fireworks.ResponseStreamLine;
+using PerplexityResponseStreamLine = AIStudio.Provider.Perplexity.ResponseStreamLine;
+
+namespace AIStudio.Tests.Serialization;
+
+public static partial class JsonTestRoots
+{
+    /// <summary>
+    /// What AI Studio sends to LLM providers.
+    /// </summary>
+    public static IEnumerable<TestCaseData> ProviderRequests()
+    {
+        TestHost.PrepareStaticState();
+        var options = ProviderJsonOptions.OPTIONS;
+
+        yield return CaseWithNamespace(typeof(ChatCompletionAPIRequest), options);
+        yield return CaseWithNamespace(typeof(ResponsesAPIRequest), options);
+        yield return CaseWithNamespace(typeof(ChatRequest), options);
+
+        //
+        // The messages and their parts, which converters write as the type they are of:
+        //
+        foreach (var type in new[] { typeof(IMessageBase), typeof(ISubContent), typeof(ISubContentImageUrl), typeof(ISubContentImageSource) }.SelectMany(ImplementationsOf))
+            yield return CaseWithNamespace(type, options);
+
+        //
+        // What a request holds as an object, which gets written as the type it is of, too. The additional API
+        // parameters hold the values the parser of the provider settings reads, and the input of the Responses API
+        // holds the items of an earlier answer as they came in:
+        //
+        foreach (var type in new[] { typeof(string), typeof(int), typeof(long), typeof(double), typeof(decimal), typeof(bool), typeof(Dictionary<string, object>), typeof(List<object>), typeof(JsonElement) })
+            yield return Case(new(type, options), "value of a request");
+
+        yield return Case(new(ProviderToolAdapters.ToChatCompletionTool(JsonSampleRequests.Tool(), hostEnforcesStrict: true).GetType(), options), "tool of a Chat Completions API");
+        yield return CaseWithNamespace(typeof(ResponsesFunctionTool), options);
+        yield return CaseWithNamespace(typeof(ResponsesFunctionCallOutputItem), options);
+    }
+
+    /// <summary>
+    /// What AI Studio receives from LLM providers.
+    /// </summary>
+    public static IEnumerable<TestCaseData> ProviderAnswers()
+    {
+        TestHost.PrepareStaticState();
+        var options = ProviderJsonOptions.OPTIONS;
+
+        // The lists of models:
+        yield return CaseWithNamespace(typeof(AIStudio.Provider.OpenAI.ModelsResponse), options);
+        yield return CaseWithNamespace(typeof(AIStudio.Provider.Mistral.ModelsResponse), options);
+        yield return CaseWithNamespace(typeof(AIStudio.Provider.SelfHosted.ModelsResponse), options);
+        yield return CaseWithNamespace(typeof(AIStudio.Provider.HuggingFace.ModelsResponse), options);
+        yield return Case(new(typeof(IList<HubModel>), options), "HuggingFace");
+        yield return CaseWithNamespace(typeof(RequestyModelsResponse), options);
+        yield return CaseWithNamespace(typeof(OpenRouterModelsResponse), options);
+        yield return CaseWithNamespace(typeof(GroqModelsResponse), options);
+
+        // The lines of streamed answers:
+        yield return CaseWithNamespace(typeof(ChatCompletionDeltaStreamLine), options);
+        yield return CaseWithNamespace(typeof(ChatCompletionAnnotationStreamLine), options);
+        yield return CaseWithNamespace(typeof(ChatCompletionToolStreamLine), options);
+        yield return CaseWithNamespace(typeof(ResponsesDeltaStreamLine), options);
+        yield return CaseWithNamespace(typeof(ResponsesAnnotationStreamLine), options);
+        yield return CaseWithNamespace(typeof(ResponsesCompletedStreamLine), options);
+        yield return CaseWithNamespace(typeof(AnthropicResponseStreamLine), options);
+        yield return CaseWithNamespace(typeof(AnthropicStreamLine), options);
+        yield return CaseWithNamespace(typeof(FireworksResponseStreamLine), options);
+        yield return CaseWithNamespace(typeof(PerplexityResponseStreamLine), options);
+
+        //
+        // The annotations, which a converter reads as the type their JSON tells:
+        //
+        foreach (var type in ImplementationsOf(typeof(Annotation)))
+            yield return CaseWithNamespace(type, options);
+
+        // Transcriptions and embeddings, where a converter reads the embeddings of Google as one or as a list:
+        yield return CaseWithNamespace(typeof(TranscriptionResponse), options);
+        yield return CaseWithNamespace(typeof(EmbeddingResponse), options);
+        yield return CaseWithNamespace(typeof(GoogleEmbeddingResponse), options);
+        yield return CaseWithNamespace(typeof(GoogleEmbedding), options);
+        yield return Case(new(typeof(List<GoogleEmbedding>), options), "Google");
+    }
+}

app/Tests/Serialization/JsonTestRoots.Runtime.cs

@@ -0,0 +1,103 @@
+using System.Reflection;
+using System.Text.Json;
+
+using AIStudio.Tools;
+using AIStudio.Tools.Databases.VectorStore;
+using AIStudio.Tools.Rust;
+using AIStudio.Tools.Services;
+
+namespace AIStudio.Tests.Serialization;
+
+public static partial class JsonTestRoots
+{
+    /// <summary>
+    /// What AI Studio sends to its runtime.
+    /// </summary>
+    public static IEnumerable<TestCaseData> RuntimeRequests()
+    {
+        TestHost.PrepareStaticState();
+        var options = RustService.JSON_OPTIONS;
+
+        yield return Case(new(typeof(SelectSecretRequest), options));
+        yield return Case(new(typeof(StoreSecretRequest), options));
+        yield return Case(new(typeof(RustService.ShareFileRequest), options));
+        yield return Case(new(typeof(PreviousDirectory), options));
+        yield return Case(new(typeof(SelectFileOptions), options));
+        yield return Case(new(typeof(SaveFileOptions), options));
+        yield return Case(new(typeof(OpenPathRequest), options));
+        yield return Case(new(typeof(OpenDocumentRequest), options));
+        yield return Case(new(typeof(RegisterShortcutRequest), options));
+        yield return Case(new(typeof(ValidateShortcutRequest), options));
+        yield return Case(new(typeof(SetInterfaceSizeRequest), options));
+        yield return Case(new(typeof(CreateMediaJobRequest), options));
+        yield return Case(new(typeof(LogEventRequest), options));
+
+        // Every request of the vector store:
+        foreach (var type in typeof(QdrantEdgeClientImplementation).GetNestedTypes(BindingFlags.NonPublic).Where(type => type.Name.EndsWith("Request", StringComparison.Ordinal)).OrderBy(type => type.Name, StringComparer.Ordinal))
+            yield return Case(new(type, options));
+
+        // The prompt injection filter, which gets called with the defaults of HttpClient, i.e., with camel case:
+        yield return Case(new(typeof(SanitizePromptInjectionsRequest), JsonSerializerOptions.Web));
+        yield return Case(new(typeof(SanitizePromptInjectionsBatchRequest), JsonSerializerOptions.Web));
+    }
+
+    /// <summary>
+    /// What AI Studio receives from its runtime.
+    /// </summary>
+    public static IEnumerable<TestCaseData> RuntimeAnswers()
+    {
+        TestHost.PrepareStaticState();
+        var options = RustService.JSON_OPTIONS;
+
+        yield return Case(new(typeof(RequestedSecret), options));
+        yield return Case(new(typeof(StoreSecretResponse), options));
+        yield return Case(new(typeof(DeleteSecretResponse), options));
+        yield return Case(new(typeof(ShareFileResponse), options));
+        yield return Case(new(typeof(ImagePrepareResponse), options));
+        yield return Case(new(typeof(PreparedModelImage), options));
+        yield return Case(new(typeof(TauriEvent), options));
+        yield return Case(new(typeof(UpdateResponse), options));
+        yield return Case(new(typeof(SetClipboardResponse), options));
+        yield return Case(new(typeof(DirectorySelectionResponse), options));
+        yield return Case(new(typeof(FileSelectionResponse), options));
+        yield return Case(new(typeof(FilesSelectionResponse), options));
+        yield return Case(new(typeof(FileSaveResponse), options));
+        yield return Case(new(typeof(OpenPathResponse), options));
+        yield return Case(new(typeof(OpenDocumentResponse), options));
+        yield return Case(new(typeof(ShortcutRegistrationResult), options));
+        yield return Case(new(typeof(ShortcutValidationResponse), options));
+        yield return Case(new(typeof(ShortcutResponse), options));
+        yield return Case(new(typeof(RuntimeInfoResponse), options));
+        yield return Case(new(typeof(AppExitResponse), options));
+        yield return Case(new(typeof(AppRestartResponse), options));
+        yield return Case(new(typeof(InterfaceSizeResponse), options));
+        yield return Case(new(typeof(CreateMediaJobResponse), options));
+        yield return Case(new(typeof(MediaJobEvent), options));
+        yield return Case(new(typeof(List<EnterpriseConfig>), options));
+        yield return Case(new(typeof(GetLogPathsResponse), options));
+        yield return Case(new(typeof(TokenizerResponse), options));
+
+        // The vector store, with the result of every query its client sends:
+        yield return Case(new(typeof(QdrantEdgeInfo), options));
+        yield return Case(new(typeof(RustService.DatabaseOperationResponse), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<VectorStoreEnsureResult>), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<bool?>), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<List<VectorSearchResult>>), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<List<StoredVector>>), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<VectorStoreBackupPreparation>), options));
+        yield return Case(new(typeof(RustService.DatabaseQueryResponse<long?>), options));
+
+        //
+        // The events of a file extraction, which get read with the defaults of System.Text.Json. A converter reads
+        // their metadata as the type the JSON tells:
+        //
+        yield return Case(new(typeof(ContentStreamSseEvent), JsonSerializerOptions.Default));
+        yield return Case(new(typeof(string), JsonSerializerOptions.Default), "error of a file extraction");
+        foreach (var type in ImplementationsOf(typeof(ContentStreamSseMetadata)))
+            yield return Case(new(type, JsonSerializerOptions.Default));
+
+        // The prompt injection filter, which gets called with the defaults of HttpClient, i.e., with camel case:
+        yield return Case(new(typeof(SanitizePromptInjectionsResponse), JsonSerializerOptions.Web));
+        yield return Case(new(typeof(SanitizePromptInjectionsBatchResponse), JsonSerializerOptions.Web));
+    }
+}

app/Tests/Serialization/JsonTestRoots.Services.cs

@@ -0,0 +1,38 @@
+using AIStudio.Tools.ERIClient;
+using AIStudio.Tools.ERIClient.DataModel;
+using AIStudio.Tools.ToolCallingSystem.ToolCallingImplementations.WebSearch;
+using AIStudio.Tools.ToolCallingSystem.ToolCallingImplementations.WebSearch.Staan;
+using AIStudio.Tools.ToolCallingSystem.ToolCallingImplementations.WebSearch.Tavily;
+
+namespace AIStudio.Tests.Serialization;
+
+public static partial class JsonTestRoots
+{
+    /// <summary>
+    /// What AI Studio sends to ERI servers and to search services.
+    /// </summary>
+    public static IEnumerable<TestCaseData> ServiceRequests()
+    {
+        TestHost.PrepareStaticState();
+        yield return Case(new(typeof(RetrievalRequest), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(StaanSearchRequest), WebSearchJson.OPTIONS));
+        yield return Case(new(typeof(TavilySearchRequest), WebSearchJson.OPTIONS));
+    }
+
+    /// <summary>
+    /// What AI Studio receives from ERI servers and from search services.
+    /// </summary>
+    public static IEnumerable<TestCaseData> ServiceAnswers()
+    {
+        TestHost.PrepareStaticState();
+        yield return Case(new(typeof(List<AuthScheme>), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(AuthResponse), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(DataSourceInfo), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(List<EmbeddingInfo>), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(List<RetrievalInfo>), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(List<Context>), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(SecurityRequirements), ERIClientBase.JSON_OPTIONS));
+        yield return Case(new(typeof(StaanSearchResponse), WebSearchJson.OPTIONS));
+        yield return Case(new(typeof(TavilySearchResponse), WebSearchJson.OPTIONS));
+    }
+}

app/Tests/Serialization/JsonTestRoots.cs

@@ -1,3 +1,5 @@
+using System.Text.Json;
+
 using AIStudio.Assistants.SWOTAnalysis;
 using AIStudio.Chat;
 using AIStudio.Settings;
@@ -15,9 +17,11 @@ namespace AIStudio.Tests.Serialization;
 /// </summary>
 /// <remarks>
 /// Only the outermost types belong here: whatever they hold gets checked along with them. Add a type whenever
-/// AI Studio starts to store a new kind of file, with the options it stores the file with.
+/// AI Studio starts to store a new kind of file or to exchange a new kind of message, with the options it uses
+/// for them. What AI Studio sends is listed apart from what it receives: only what it reads has to keep the
+/// defaults of a new object.
 /// </remarks>
-public static class JsonTestRoots
+public static partial class JsonTestRoots
 {
     /// <summary>
     /// The data AI Studio keeps on the disk of the user.
@@ -67,6 +71,27 @@ public static class JsonTestRoots
         return new TestCaseData(root).SetArgDisplayNames(purpose is null ? root.ToString() : $"{root}, {purpose}");
     }
 
+    /// <summary>
+    /// Names the case after its type together with the last part of the namespace, which tells apart types of the
+    /// same name, e.g., the lists of models of two providers.
+    /// </summary>
+    private static TestCaseData CaseWithNamespace(Type type, JsonSerializerOptions options)
+    {
+        var typeNamespace = type.Namespace!;
+        return Case(new(type, options), typeNamespace[(typeNamespace.LastIndexOf('.') + 1)..]);
+    }
+
+    /// <summary>
+    /// Returns the classes and structs of AI Studio which are the given type.
+    /// </summary>
+    /// <remarks>
+    /// A converter which writes a value as the type it is of meets these types without any property naming them.
+    /// Listing them all here keeps a new one from going unchecked.
+    /// </remarks>
+    private static IEnumerable<Type> ImplementationsOf(Type type) => typeof(Program).Assembly.GetTypes()
+        .Where(candidate => candidate is { IsAbstract: false, IsInterface: false, IsGenericTypeDefinition: false } && type.IsAssignableFrom(candidate))
+        .OrderBy(candidate => candidate.FullName, StringComparer.Ordinal);
+
     private static IEnumerable<Type> ManagedSettingValueTypes()
     {
         //