Initial version of prompt token replacements

src/dotnet/Common/Models/ResourceProviders/Prompt/MultipartPrompt.cs

@@ -20,6 +20,12 @@ public class MultipartPrompt : PromptBase
         [JsonPropertyName("suffix")]
         public string? Suffix { get; set; }
 
+        /// <summary>
+        /// Optional string token replacements for the prompt.
+        /// </summary>
+        [JsonPropertyName("token_replacements")]
+        public TokenReplacementDefinition[] TokenReplacements { get; set; } = [];
+
         /// <summary>
         /// Set default property values.
         /// </summary>

src/dotnet/Common/Models/ResourceProviders/Prompt/TokenReplacementDefinition.cs

@@ -0,0 +1,22 @@
+using System.Text.Json.Serialization;
+
+namespace FoundationaLLM.Common.Models.ResourceProviders.Prompt
+{
+    /// <summary>
+    /// String text token replacement definition.
+    /// </summary>
+    public class TokenReplacementDefinition
+    {
+        /// <summary>
+        /// The token to be replaced.
+        /// </summary>
+        [JsonPropertyName("token")]
+        public required string Token { get; set; }
+
+        /// <summary>
+        /// The code to compute the replacement value.
+        /// </summary>
+        [JsonPropertyName("compute_code")]
+        public required string ComputeCode { get; set; }
+    }
+}

src/dotnet/Orchestration/Orchestration.csproj

@@ -16,6 +16,7 @@
   </ItemGroup>
 
 	<ItemGroup>
+		<PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="4.12.0" />
 		<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
 	</ItemGroup>
 

src/dotnet/Orchestration/Orchestration/OrchestrationBuilder.cs

@@ -16,6 +16,7 @@
 using FoundationaLLM.Common.Models.ResourceProviders.Prompt;
 using FoundationaLLM.Common.Models.ResourceProviders.Vectorization;
 using FoundationaLLM.Orchestration.Core.Interfaces;
+using FoundationaLLM.Orchestration.Core.Services.TokenReplacement;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -204,7 +205,7 @@ await cosmosDBService.PatchOperationsItemPropertiesAsync<LongRunningOperationCon
             var agentWorkflow = agentBase.Workflow;
             AIModelBase? mainAIModel = null;
             APIEndpointConfiguration? mainAIModelAPIEndpointConfiguration = null;
-
+                        
             if (agentWorkflow is not null)
             {
                 foreach (var resourceObjectId in agentWorkflow.ResourceObjectIds.Values)
@@ -256,6 +257,18 @@ await cosmosDBService.PatchOperationsItemPropertiesAsync<LongRunningOperationCon
                                 var retrievedPrompt = await promptResourceProvider.GetResourceAsync<PromptBase>(
                                            resourceObjectId.ObjectId,
                                            currentUserIdentity);
+
+                                if(retrievedPrompt is MultipartPrompt multipartPrompt)
+                                {
+                                    //check for token replacements, multipartPrompt variable has the same reference as retrievedPrompt therefore this edits the prefix/suffix in place
+                                    if (multipartPrompt is not null && multipartPrompt.TokenReplacements != null && multipartPrompt.TokenReplacements.Length > 0)
+                                    {
+                                        var tokenReplacementEngine = new TokenReplacementEngine(multipartPrompt.TokenReplacements.ToList());
+                                        multipartPrompt.Prefix = await tokenReplacementEngine.ReplaceTokensAsync(multipartPrompt.Prefix!);
+                                        multipartPrompt.Suffix = await tokenReplacementEngine.ReplaceTokensAsync(multipartPrompt.Suffix!);
+                                    }
+                                }
+
                                 explodedObjectsManager.TryAdd(
                                     retrievedPrompt.ObjectId!,
                                     retrievedPrompt);

src/dotnet/Orchestration/Services/TokenReplacement/TokenReplacementEngine.cs

@@ -0,0 +1,68 @@
+using System.Text.RegularExpressions;
+using FoundationaLLM.Common.Models.ResourceProviders.Prompt;
+using Microsoft.CodeAnalysis.CSharp.Scripting;
+using Microsoft.CodeAnalysis.Scripting;
+
+namespace FoundationaLLM.Orchestration.Core.Services.TokenReplacement
+{
+    /// <summary>
+    /// Token replacement engine, responsible for replacing tokens in a string with their computed values.
+    /// </summary>
+    public class TokenReplacementEngine
+    {
+        private readonly List<TokenReplacementDefinition> _tokenReplacements;
+        private readonly ScriptOptions _scriptOptions;
+
+        /// <summary>
+        /// Creates an instance of the <see cref="TokenReplacementEngine"/> class.
+        /// </summary>
+        /// <param name="tokenReplacements"></param>
+        public TokenReplacementEngine(List<TokenReplacementDefinition> tokenReplacements)
+        {
+            _tokenReplacements = tokenReplacements;
+
+            // Define script options, such as referencing necessary assemblies and namespaces
+            _scriptOptions = ScriptOptions.Default              
+                .AddImports("System");
+        }
+
+        /// <summary>
+        /// Replaces tokens in the input string with their corresponding computed values.
+        /// </summary>
+        /// <param name="input">The input string containing tokens to be replaced.</param>
+        /// <returns>A task that represents the asynchronous operation. The task result contains the string with tokens replaced.</returns>
+        public async Task<string> ReplaceTokensAsync(string input)
+        {
+            if (string.IsNullOrWhiteSpace(input))
+            {
+                return input;
+            }
+            string pattern = @"{{\s*(\w+)\s*}}";
+            return await Task.Run(() => Regex.Replace(input, pattern, match =>
+            {
+                string tokenName = match.Groups[1].Value;
+                var tokenReplacement = _tokenReplacements.Find(tr => tr.Token == $"{{{{{tokenName}}}}}");
+
+                if (tokenReplacement != null)
+                {
+                    try
+                    {
+                        // Evaluate the compute code
+                        var result = CSharpScript.EvaluateAsync<string>(
+                            tokenReplacement.ComputeCode,
+                            _scriptOptions).Result;
+                        return result;
+                    }
+                    catch (Exception ex)
+                    {
+                        // Handle errors in compute code
+                        return $"[Error: {ex.Message}]";
+                    }
+                }
+
+                // If token not found, return it unchanged or handle as needed
+                return match.Value;
+            }, RegexOptions.IgnoreCase));
+        }
+    }
+}