#1262 - fix(genai): correct Anthropic system prompt placement and add provider unit tests

packages/genai/lib/interface/model_providers/anthropic.dart

@@ -30,9 +30,15 @@ class AnthropicModel extends ModelProvider {
             ),
       body: kJsonEncoder.convert({
         "model": aiRequestModel.model,
+        if (aiRequestModel.systemPrompt.isNotEmpty)
+          "system": aiRequestModel.systemPrompt,
         "messages": [
-          {"role": "system", "content": aiRequestModel.systemPrompt},
-          {"role": "user", "content": aiRequestModel.userPrompt},
+          {
+            "role": "user",
+            "content": aiRequestModel.userPrompt.isNotEmpty
+                ? aiRequestModel.userPrompt
+                : "Generate",
+          },
         ],
         ...aiRequestModel.getModelConfigMap(),
         if (aiRequestModel.stream ?? false) ...{'stream': true},

packages/genai/test/interface/model_providers/anthropic_test.dart

@@ -0,0 +1,168 @@
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:genai/interface/consts.dart';
+import 'package:genai/interface/model_providers/anthropic.dart';
+import 'package:genai/models/ai_request_model.dart';
+
+void main() {
+  group('AnthropicModel', () {
+    test('should return default AIRequestModel with Anthropic provider', () {
+      final defaultModel = AnthropicModel.instance.defaultAIRequestModel;
+
+      expect(defaultModel.modelApiProvider, equals(ModelAPIProvider.anthropic));
+      expect(defaultModel.url, equals(kAnthropicUrl));
+    });
+
+    test('should return null when aiRequestModel is null', () {
+      final result = AnthropicModel.instance.createRequest(null);
+      expect(result, isNull);
+    });
+
+    test('should set anthropic-version header', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        apiKey: 'test-key',
+        userPrompt: 'Hello',
+        systemPrompt: 'You are helpful',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+
+      expect(
+        httpReq.headers?.any(
+          (h) => h.name == 'anthropic-version' && h.value == '2023-06-01',
+        ),
+        isTrue,
+      );
+    });
+
+    test('should place system prompt as top-level field, not inside messages',
+        () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        apiKey: 'test-key',
+        userPrompt: 'Hello',
+        systemPrompt: 'You are a helpful assistant',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+
+      // system prompt must be a top-level key
+      expect(body['system'], equals('You are a helpful assistant'));
+
+      // messages must contain only the user role, never system
+      final messages = body['messages'] as List;
+      expect(messages, hasLength(1));
+      expect(messages[0]['role'], equals('user'));
+      expect(
+        messages.any((m) => m['role'] == 'system'),
+        isFalse,
+        reason: 'Anthropic API does not support role:system inside messages',
+      );
+    });
+
+    test('should omit system field when systemPrompt is empty', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        userPrompt: 'Hello',
+        systemPrompt: '',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+
+      expect(body.containsKey('system'), isFalse);
+    });
+
+    test('should use "Generate" as fallback when userPrompt is empty', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        userPrompt: '',
+        systemPrompt: 'sys',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+      final messages = body['messages'] as List;
+
+      expect(messages[0]['content'], equals('Generate'));
+    });
+
+    test('should include stream:true in body when streaming is enabled', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        apiKey: 'test-key',
+        userPrompt: 'Hello',
+        systemPrompt: 'Sys',
+        stream: true,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+
+      expect(body['stream'], isTrue);
+    });
+
+    test('should not include stream key when streaming is disabled', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        userPrompt: 'Hello',
+        systemPrompt: 'Sys',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+
+      expect(body.containsKey('stream'), isFalse);
+    });
+
+    test('should format non-streaming output correctly', () {
+      final response = {
+        'content': [
+          {'text': 'Hello from Claude'},
+        ],
+      };
+
+      final output = AnthropicModel.instance.outputFormatter(response);
+      expect(output, equals('Hello from Claude'));
+    });
+
+    test('should return null for malformed non-streaming output', () {
+      final output = AnthropicModel.instance.outputFormatter({});
+      expect(output, isNull);
+    });
+
+    test('should use POST method', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.anthropic,
+        url: kAnthropicUrl,
+        model: 'claude-3-5-sonnet-latest',
+        userPrompt: 'Hi',
+        systemPrompt: '',
+        stream: false,
+      );
+
+      final httpReq = AnthropicModel.instance.createRequest(req)!;
+      expect(httpReq.method.name, equals('post'));
+    });
+  });
+}

packages/genai/test/interface/model_providers/ollama_test.dart

@@ -0,0 +1,92 @@
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:genai/interface/consts.dart';
+import 'package:genai/interface/model_providers/ollama.dart';
+import 'package:genai/models/ai_request_model.dart';
+
+void main() {
+  group('OllamaModel', () {
+    test('should return default AIRequestModel with Ollama provider', () {
+      final defaultModel = OllamaModel.instance.defaultAIRequestModel;
+
+      expect(defaultModel.modelApiProvider, equals(ModelAPIProvider.ollama));
+      expect(defaultModel.url, equals(kOllamaUrl));
+    });
+
+    test('should only include temperature and top_p model configs by default',
+        () {
+      final defaultModel = OllamaModel.instance.defaultAIRequestModel;
+      final configIds = defaultModel.modelConfigs.map((c) => c.id).toList();
+
+      expect(configIds, containsAll(['temperature', 'top_p']));
+      expect(configIds, isNot(contains('max_tokens')));
+    });
+
+    test('should use OpenAI-compatible request format', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.ollama,
+        url: kOllamaUrl,
+        model: 'llama3',
+        userPrompt: 'Hello',
+        systemPrompt: 'You are helpful',
+        stream: false,
+      );
+
+      final httpReq = OllamaModel.instance.createRequest(req)!;
+      final body = jsonDecode(httpReq.body!) as Map<String, dynamic>;
+
+      // Ollama inherits OpenAI format: system prompt in messages
+      expect(body.containsKey('messages'), isTrue);
+      final messages = body['messages'] as List;
+      expect(messages[0]['role'], equals('system'));
+      expect(messages[1]['role'], equals('user'));
+    });
+
+    test('should use POST method and point to Ollama URL', () {
+      const req = AIRequestModel(
+        modelApiProvider: ModelAPIProvider.ollama,
+        url: kOllamaUrl,
+        model: 'llama3',
+        userPrompt: 'Hi',
+        systemPrompt: '',
+        stream: false,
+      );
+
+      final httpReq = OllamaModel.instance.createRequest(req)!;
+      expect(httpReq.method.name, equals('post'));
+      expect(httpReq.url, equals(kOllamaUrl));
+    });
+
+    test('should format output correctly (OpenAI-compatible)', () {
+      final response = {
+        'choices': [
+          {
+            'message': {'content': '  Ollama response  '},
+          },
+        ],
+      };
+
+      final output = OllamaModel.instance.outputFormatter(response);
+      expect(output, equals('Ollama response'));
+    });
+
+    test('should format streaming delta output correctly', () {
+      final response = {
+        'choices': [
+          {
+            'delta': {'content': 'stream chunk'},
+          },
+        ],
+      };
+
+      final output = OllamaModel.instance.streamOutputFormatter(response);
+      expect(output, equals('stream chunk'));
+    });
+
+    test('should return null when aiRequestModel is null', () {
+      final result = OllamaModel.instance.createRequest(null);
+      expect(result, isNull);
+    });
+  });
+}