Add Claude AI Integration for Elsa Workflows

Elsa.Extensions.sln

@@ -277,6 +277,14 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "diagnostics", "diagnostics"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.OpenTelemetry", "src\modules\diagnostics\Elsa.OpenTelemetry\Elsa.OpenTelemetry.csproj", "{28D04FA3-4DCC-4137-8ED4-9F6F1A815909}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ai", "ai", "{E0C1E9D1-ECAF-4C86-B623-E3C748E82BCF}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.Integrations.AnthropicClaude", "src\modules\ai\Elsa.Integrations.AnthropicClaude\Elsa.Integrations.AnthropicClaude.csproj", "{A83B6B99-58AA-4DB2-801A-514361789759}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ai", "ai", "{5F052B47-53DB-43B8-852D-D52DC967DE7B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.Integrations.AnthropicClaude.Tests", "test\modules\ai\Elsa.Integrations.AnthropicClaude.Tests\Elsa.Integrations.AnthropicClaude.Tests.csproj", "{793F0184-6F08-4D9A-8EC2-16A5560AD9B7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -631,6 +639,14 @@ Global
 		{28D04FA3-4DCC-4137-8ED4-9F6F1A815909}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{28D04FA3-4DCC-4137-8ED4-9F6F1A815909}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{28D04FA3-4DCC-4137-8ED4-9F6F1A815909}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A83B6B99-58AA-4DB2-801A-514361789759}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A83B6B99-58AA-4DB2-801A-514361789759}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A83B6B99-58AA-4DB2-801A-514361789759}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A83B6B99-58AA-4DB2-801A-514361789759}.Release|Any CPU.Build.0 = Release|Any CPU
+		{793F0184-6F08-4D9A-8EC2-16A5560AD9B7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{793F0184-6F08-4D9A-8EC2-16A5560AD9B7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{793F0184-6F08-4D9A-8EC2-16A5560AD9B7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{793F0184-6F08-4D9A-8EC2-16A5560AD9B7}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -755,6 +771,10 @@ Global
 		{8D0EC628-350F-47FC-8B36-DD98B4B7CC93} = {30CF0330-4B09-4784-B499-46BED303810B}
 		{28D04FA3-4DCC-4137-8ED4-9F6F1A815909} = {8D0EC628-350F-47FC-8B36-DD98B4B7CC93}
 		{04265302-AF6B-4627-807C-DE9E1699D7C9} = {30CF0330-4B09-4784-B499-46BED303810B}
+		{E0C1E9D1-ECAF-4C86-B623-E3C748E82BCF} = {30CF0330-4B09-4784-B499-46BED303810B}
+		{A83B6B99-58AA-4DB2-801A-514361789759} = {E0C1E9D1-ECAF-4C86-B623-E3C748E82BCF}
+		{5F052B47-53DB-43B8-852D-D52DC967DE7B} = {3DDE6F89-531C-47F8-9CD7-7A4E6984FA48}
+		{793F0184-6F08-4D9A-8EC2-16A5560AD9B7} = {5F052B47-53DB-43B8-852D-D52DC967DE7B}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {11A771DA-B728-445E-8A88-AE1C84C3B3A6}

src/modules/ai/Elsa.Integrations.AnthropicClaude/Activities/ClaudeActivity.cs

@@ -0,0 +1,32 @@
+using Elsa.Integrations.AnthropicClaude.Services;
+using Elsa.Workflows;
+using Elsa.Workflows.Attributes;
+using Elsa.Workflows.Models;
+
+namespace Elsa.Integrations.AnthropicClaude.Activities;
+
+/// <summary>
+/// Base class for all Claude-related activities.
+/// </summary>
+public abstract class ClaudeActivity : Activity
+{
+    /// <summary>
+    /// The Anthropic Claude API key.
+    /// </summary>
+    [Input(
+        Description = "The Anthropic Claude API key. Get your API key from https://console.anthropic.com/",
+        UIHint = "password")]
+    public Input<string> ApiKey { get; set; } = null!;
+
+    /// <summary>
+    /// Gets a configured Claude API client.
+    /// </summary>
+    /// <param name="context">The activity execution context.</param>
+    /// <returns>A configured Claude API client.</returns>
+    protected ClaudeApiClient GetClient(ActivityExecutionContext context)
+    {
+        var clientFactory = context.GetRequiredService<ClaudeClientFactory>();
+        var apiKey = context.Get(ApiKey)!;
+        return clientFactory.GetClient(apiKey);
+    }
+}

src/modules/ai/Elsa.Integrations.AnthropicClaude/Activities/CreatePrompt.cs

@@ -0,0 +1,173 @@
+using Elsa.Integrations.AnthropicClaude.Models;
+using Elsa.Workflows;
+using Elsa.Workflows.Attributes;
+using Elsa.Workflows.Models;
+using JetBrains.Annotations;
+
+namespace Elsa.Integrations.AnthropicClaude.Activities;
+
+/// <summary>
+/// Creates a prompt and sends it to Claude AI for completion.
+/// </summary>
+[Activity(
+    "Elsa.AnthropicClaude.Completions",
+    "Anthropic Claude",
+    "Creates a prompt based on structured input messages and gets a response from Claude AI.",
+    DisplayName = "Create Prompt")]
+[UsedImplicitly]
+public class CreatePrompt : ClaudeActivity
+{
+    /// <summary>
+    /// The model to use for the completion (e.g., claude-3-sonnet-20240229, claude-3-haiku-20240307).
+    /// </summary>
+    [Input(
+        Description = "The Claude model to use for completion. Popular options: claude-3-sonnet-20240229, claude-3-haiku-20240307, claude-3-opus-20240229",
+        DefaultValue = "claude-3-sonnet-20240229")]
+    public Input<string> Model { get; set; } = new("claude-3-sonnet-20240229");
+
+    /// <summary>
+    /// The system prompt that defines Claude's behavior and context.
+    /// </summary>
+    [Input(
+        Description = "System prompt that defines Claude's behavior, role, and context for the conversation.",
+        UIHint = "multiline")]
+    public Input<string?> SystemPrompt { get; set; } = null!;
+
+    /// <summary>
+    /// The user message or prompt to send to Claude.
+    /// </summary>
+    [Input(
+        Description = "The user message or prompt to send to Claude.",
+        UIHint = "multiline")]
+    public Input<string> UserMessage { get; set; } = null!;
+
+    /// <summary>
+    /// Previous messages in the conversation (JSON array of messages with 'role' and 'content' properties).
+    /// </summary>
+    [Input(
+        Description = "Previous messages in the conversation as a JSON array. Each message should have 'role' (user/assistant) and 'content' properties.",
+        UIHint = "multiline")]
+    public Input<string?> PreviousMessages { get; set; } = null!;
+
+    /// <summary>
+    /// Maximum number of tokens to generate in the response.
+    /// </summary>
+    [Input(
+        Description = "Maximum number of tokens to generate in the response (1-4096).",
+        DefaultValue = 1024)]
+    public Input<int> MaxTokens { get; set; } = new(1024);
+
+    /// <summary>
+    /// Temperature for controlling randomness (0.0 = focused, 1.0 = creative).
+    /// </summary>
+    [Input(
+        Description = "Temperature for controlling response randomness. 0.0 = very focused, 1.0 = very creative.",
+        DefaultValue = 0.7)]
+    public Input<double?> Temperature { get; set; } = new(0.7);
+
+    /// <summary>
+    /// Stop sequences that will end the generation when encountered.
+    /// </summary>
+    [Input(
+        Description = "Stop sequences that will end generation when encountered (comma-separated).")]
+    public Input<string?> StopSequences { get; set; } = null!;
+
+    /// <summary>
+    /// The generated response from Claude.
+    /// </summary>
+    [Output(Description = "The text response generated by Claude.")]
+    public Output<string> Response { get; set; } = null!;
+
+    /// <summary>
+    /// The full response object containing additional metadata.
+    /// </summary>
+    [Output(Description = "The complete response object with metadata including token usage.")]
+    public Output<ClaudeCompletionResponse> FullResponse { get; set; } = null!;
+
+    /// <summary>
+    /// The number of input tokens used.
+    /// </summary>
+    [Output(Description = "The number of input tokens used for this request.")]
+    public Output<int> InputTokens { get; set; } = null!;
+
+    /// <summary>
+    /// The number of output tokens generated.
+    /// </summary>
+    [Output(Description = "The number of output tokens generated in the response.")]
+    public Output<int> OutputTokens { get; set; } = null!;
+
+    /// <summary>
+    /// Executes the activity.
+    /// </summary>
+    protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)
+    {
+        var model = context.Get(Model)!;
+        var systemPrompt = context.Get(SystemPrompt);
+        var userMessage = context.Get(UserMessage)!;
+        var previousMessagesJson = context.Get(PreviousMessages);
+        var maxTokens = context.Get(MaxTokens);
+        var temperature = context.Get(Temperature);
+        var stopSequencesInput = context.Get(StopSequences);
+
+        var client = GetClient(context);
+
+        // Build the messages list
+        var messages = new List<ClaudeMessage>();
+
+        // Add previous messages if provided
+        if (!string.IsNullOrWhiteSpace(previousMessagesJson))
+        {
+            try
+            {
+                var previousMessages = System.Text.Json.JsonSerializer.Deserialize<List<ClaudeMessage>>(previousMessagesJson);
+                if (previousMessages != null)
+                {
+                    messages.AddRange(previousMessages);
+                }
+            }
+            catch (System.Text.Json.JsonException)
+            {
+                // If JSON parsing fails, ignore previous messages and continue
+            }
+        }
+
+        // Add the current user message
+        messages.Add(new ClaudeMessage
+        {
+            Role = "user",
+            Content = userMessage
+        });
+
+        // Parse stop sequences
+        List<string>? stopSequences = null;
+        if (!string.IsNullOrWhiteSpace(stopSequencesInput))
+        {
+            stopSequences = stopSequencesInput.Split(',', StringSplitOptions.RemoveEmptyEntries)
+                                            .Select(s => s.Trim())
+                                            .ToList();
+        }
+
+        // Create the request
+        var request = new ClaudeCompletionRequest
+        {
+            Model = model,
+            MaxTokens = maxTokens,
+            Messages = messages,
+            System = systemPrompt,
+            Temperature = temperature,
+            StopSequences = stopSequences
+        };
+
+        // Make the API call
+        var response = await client.CreateCompletionAsync(request, context.CancellationToken);
+
+        // Extract the response text
+        var responseText = response.Content.FirstOrDefault()?.Text ?? string.Empty;
+
+        // Set outputs
+        context.Set(Response, responseText);
+        context.Set(FullResponse, response);
+        context.Set(InputTokens, response.Usage?.InputTokens ?? 0);
+        context.Set(OutputTokens, response.Usage?.OutputTokens ?? 0);
+    }
+}

src/modules/ai/Elsa.Integrations.AnthropicClaude/Activities/MakeAPICall.cs

@@ -0,0 +1,122 @@
+using Elsa.Workflows;
+using Elsa.Workflows.Attributes;
+using Elsa.Workflows.Models;
+using JetBrains.Annotations;
+
+namespace Elsa.Integrations.AnthropicClaude.Activities;
+
+/// <summary>
+/// Makes an arbitrary HTTP call to the Anthropic Claude API.
+/// </summary>
+[Activity(
+    "Elsa.AnthropicClaude.API",
+    "Anthropic Claude",
+    "Performs an arbitrary authorized API call to the Anthropic Claude API.",
+    DisplayName = "Make API Call")]
+[UsedImplicitly]
+public class MakeAPICall : ClaudeActivity
+{
+    /// <summary>
+    /// The HTTP method to use for the API call.
+    /// </summary>
+    [Input(
+        Description = "The HTTP method to use (GET, POST, PUT, DELETE, etc.).",
+        DefaultValue = "POST")]
+    public Input<string> HttpMethod { get; set; } = new("POST");
+
+    /// <summary>
+    /// The API endpoint to call (relative to the Claude API base URL).
+    /// </summary>
+    [Input(
+        Description = "The API endpoint to call, relative to https://api.anthropic.com/v1/ (e.g., 'messages', 'models').",
+        DefaultValue = "messages")]
+    public Input<string> Endpoint { get; set; } = new("messages");
+
+    /// <summary>
+    /// The request body as JSON string (for POST, PUT requests).
+    /// </summary>
+    [Input(
+        Description = "The request body as a JSON string. Leave empty for GET requests.",
+        UIHint = "multiline")]
+    public Input<string?> RequestBody { get; set; } = null!;
+
+    /// <summary>
+    /// Whether to validate that the request body is valid JSON before sending.
+    /// </summary>
+    [Input(
+        Description = "Whether to validate that the request body is valid JSON before sending the request.",
+        DefaultValue = true)]
+    public Input<bool> ValidateJson { get; set; } = new(true);
+
+    /// <summary>
+    /// The raw response body from the API call.
+    /// </summary>
+    [Output(Description = "The raw response body from the Claude API call.")]
+    public Output<string> ResponseBody { get; set; } = null!;
+
+    /// <summary>
+    /// Indicates whether the API call was successful (2xx status code).
+    /// </summary>
+    [Output(Description = "True if the API call was successful (2xx status code), false otherwise.")]
+    public Output<bool> Success { get; set; } = null!;
+
+    /// <summary>
+    /// Executes the activity.
+    /// </summary>
+    protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)
+    {
+        var httpMethodString = context.Get(HttpMethod)!;
+        var endpoint = context.Get(Endpoint)!;
+        var requestBody = context.Get(RequestBody);
+        var validateJson = context.Get(ValidateJson);
+
+        var client = GetClient(context);
+
+        // Validate HTTP method
+        if (!System.Net.Http.HttpMethod.TryParse(httpMethodString, out var method))
+        {
+            throw new ArgumentException($"Invalid HTTP method: {httpMethodString}");
+        }
+
+        // Validate JSON if requested and content is provided
+        if (validateJson && !string.IsNullOrWhiteSpace(requestBody))
+        {
+            try
+            {
+                System.Text.Json.JsonDocument.Parse(requestBody);
+            }
+            catch (System.Text.Json.JsonException ex)
+            {
+                throw new ArgumentException($"Invalid JSON in request body: {ex.Message}", ex);
+            }
+        }
+
+        // Ensure endpoint doesn't start with slash (we'll add it in the service)
+        if (endpoint.StartsWith("/"))
+        {
+            endpoint = endpoint.Substring(1);
+        }
+
+        try
+        {
+            // Make the API call
+            var responseBody = await client.MakeApiCallAsync(
+                method, 
+                endpoint, 
+                requestBody, 
+                context.CancellationToken);
+
+            // Set outputs
+            context.Set(ResponseBody, responseBody);
+            context.Set(Success, true);
+        }
+        catch (HttpRequestException)
+        {
+            // For HTTP errors, we still want to set Success to false but not throw
+            // The error details should be in the exception message
+            context.Set(ResponseBody, string.Empty);
+            context.Set(Success, false);
+            throw; // Re-throw to let the workflow handle the error
+        }
+    }
+}

src/modules/ai/Elsa.Integrations.AnthropicClaude/Elsa.Integrations.AnthropicClaude.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <TargetFrameworks></TargetFrameworks>
+	    <Description>
+		    Provides integration with Anthropic Claude AI for Elsa Workflows.
+	    </Description>
+	    <PackageTags>elsa extension module anthropic claude ai</PackageTags>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Elsa" />
+        <PackageReference Include="Microsoft.Extensions.Http" />
+        <PackageReference Include="System.Text.Json" />
+    </ItemGroup>
+
+</Project>