Add automatic dedent of description and instructions

In configuration, especially TOML or YAML, this allows improved readability by adding indents as needed, but still get a clean dedented string just like the C# multiline literal strings.

Author: kzu

.netconfig

@@ -159,3 +159,8 @@
 	sha = 3012d56be7554c483e5c5d277144c063969cada9
 	etag = 43c81c6c6dcdf5baee40a9e3edc5e871e473e6c954c901b82bb87a3a48888ea0
 	weak
+[file "src/Agents/Extensions/Dedent.cs"]
+	url = https://github.com/devlooped/catbag/blob/main/System/Dedent.cs
+	sha = c0a15b3c5e42a6f5e73b8e43ad3a335d7d6f3787
+	etag = fe8de7929a8ecdb631911233ae3c6bad034b26b9802e62c3521918207f6d4068
+	weak

src/Agents/ConfigurableAIAgent.cs

@@ -82,6 +82,8 @@ public override IAsyncEnumerable<AgentRunResponseUpdate> RunStreamingAsync(IEnum
     {
         var options = configSection.Get<AgentClientOptions>();
         options?.Name ??= name;
+        options?.Description = options?.Description?.Dedent();
+        options?.Instructions = options?.Instructions?.Dedent();
 
         // If there was a custom id, we must validate it didn't change since that's not supported.
         if (configuration[$"{section}:name"] is { } newname && newname != name)

src/Agents/Extensions/Dedent.cs

@@ -0,0 +1,130 @@
+// <auto-generated />
+#region License
+// MIT License
+// 
+// Copyright (c) Daniel Cazzulino
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+#endregion
+
+#nullable enable
+using System.Text;
+using System.Text.RegularExpressions;
+
+namespace System
+{
+    /// <summary>
+    /// String extension methods for text processing.
+    /// </summary>
+    static partial class StringExtensions
+    {
+        /// <summary>
+        /// Remove leading whitespace from each line of a multi-line string that is common 
+        /// to all non-empty lines. This is equivalent to Python's textwrap.dedent().
+        /// </summary>
+        /// <param name="text">The text to dedent.</param>
+        /// <returns>The dedented text.</returns>
+        /// <example>
+        /// <code>
+        /// var text = """
+        ///         Line 1
+        ///         Line 2
+        ///         Line 3
+        ///     """;
+        /// var dedented = text.Dedent();
+        /// // Result:
+        /// // Line 1
+        /// // Line 2 
+        /// // Line 3
+        /// </code>
+        /// </example>
+        public static string Dedent(this string text)
+        {
+            if (string.IsNullOrEmpty(text))
+                return text;
+
+            // Detect the line ending style used in the input
+            var lineEnding = Environment.NewLine;
+            if (text.Contains("\r\n"))
+                lineEnding = "\r\n";
+            else if (text.Contains('\r'))
+                lineEnding = "\r";
+            else if (text.Contains('\n'))
+                lineEnding = "\n";
+
+            // Split using regex to properly handle different line endings
+            var lines = NewLineExpr().Split(text);
+
+            // Remove leading and trailing empty lines
+            int start = 0;
+            int end = lines.Length - 1;
+
+            while (start < lines.Length && string.IsNullOrWhiteSpace(lines[start]))
+                start++;
+
+            while (end >= 0 && string.IsNullOrWhiteSpace(lines[end]))
+                end--;
+
+            if (start > end)
+                return string.Empty;
+
+            // Find the minimum indentation (ignoring empty lines)
+            int minIndent = int.MaxValue;
+            for (int i = start; i <= end; i++)
+            {
+                var line = lines[i];
+                if (!string.IsNullOrWhiteSpace(line))
+                {
+                    int indent = 0;
+                    while (indent < line.Length && char.IsWhiteSpace(line[indent]))
+                        indent++;
+
+                    minIndent = Math.Min(minIndent, indent);
+                }
+            }
+
+            if (minIndent == int.MaxValue || minIndent == 0)
+                minIndent = 0;
+
+            // Remove the common indentation from all lines
+            var result = new StringBuilder();
+            for (int i = start; i <= end; i++)
+            {
+                var line = lines[i];
+                if (string.IsNullOrWhiteSpace(line))
+                {
+                    if (i < end) // Don't add newline for last empty line
+                        result.Append(lineEnding);
+                }
+                else
+                {
+                    var dedentedLine = line.Length > minIndent ? line[minIndent..] : string.Empty;
+                    result.Append(dedentedLine);
+                    if (i < end)
+                        result.Append(lineEnding);
+                }
+            }
+
+            return result.ToString();
+        }
+
+        [GeneratedRegex(@"\r\n|\r|\n")]
+        private static partial Regex NewLineExpr();
+    }
+}

src/Tests/ConfigurableAgentTests.cs

@@ -38,6 +38,58 @@ public void CanConfigureAgent()
         Assert.Equal("Helpful chat agent", agent.Description);
     }
 
+    [Fact]
+    public void DedentsDescriptionAndInstructions()
+    {
+        var builder = new HostApplicationBuilder();
+
+        builder.Configuration.AddInMemoryCollection(new Dictionary<string, string?>
+        {
+            ["ai:clients:chat:modelid"] = "gpt-4.1-nano",
+            ["ai:clients:chat:apikey"] = "sk-asdfasdf",
+            ["ai:agents:bot:client"] = "chat",
+            ["ai:agents:bot:name"] = "chat",
+            ["ai:agents:bot:description"] =
+                """
+
+
+                    Line 1
+                    Line 2
+                    Line 3
+
+                """,
+            ["ai:agents:bot:instructions"] =
+                """
+                        Agent Instructions:
+                            - Step 1
+                            - Step 2
+                            - Step 3
+                """,
+            ["ai:agents:bot:options:temperature"] = "0.5",
+        });
+
+        builder.AddAIAgents();
+
+        var app = builder.Build();
+
+        var agent = app.Services.GetRequiredKeyedService<AIAgent>("chat");
+
+        Assert.Equal(
+            """
+            Line 1
+            Line 2
+            Line 3
+            """, agent.Description);
+
+        Assert.Equal(
+            """
+            Agent Instructions:
+                - Step 1
+                - Step 2
+                - Step 3
+            """, agent.GetService<ChatClientAgentOptions>()?.Instructions);
+    }
+
     [Fact]
     public void CanReloadConfiguration()
     {