4 files changed, 78 insertions, 5 deletions
diff --git a/src/Agent.Core/Ollama/IOllamaClient.cs b/src/Agent.Core/Ollama/IOllamaClient.cs
index a03a353..d1cb99f 100644
--- a/src/Agent.Core/Ollama/IOllamaClient.cs
+++ b/src/Agent.Core/Ollama/IOllamaClient.cs
@@ -1,5 +1,6 @@
 namespace Agent.Core.Ollama;
 
+using System.Text.Json;
 using Agent.Core.Tools;
 
 public interface IOllamaClient
@@ -7,5 +8,7 @@ public interface IOllamaClient
     Task<OllamaResult> ChatAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, CancellationToken cancellationToken);
     Task<OllamaResult> ChatWithToolsAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, IReadOnlyList<InternalToolDefinition> tools, CancellationToken cancellationToken) =>
         ChatAsync(messages, temperatureOverride, cancellationToken);
+    Task<OllamaResult> ChatStructuredAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, JsonElement format, CancellationToken cancellationToken) =>
+        ChatAsync(messages, temperatureOverride, cancellationToken);
     Task<bool?> SupportsVisionAsync(CancellationToken cancellationToken) => Task.FromResult<bool?>(null);
 }
diff --git a/src/Agent.Core/Ollama/OllamaClient.cs b/src/Agent.Core/Ollama/OllamaClient.cs
index bfd2210..c761081 100644
--- a/src/Agent.Core/Ollama/OllamaClient.cs
+++ b/src/Agent.Core/Ollama/OllamaClient.cs
@@ -22,10 +22,13 @@ public sealed class OllamaClient : IOllamaClient
     }
 
     public async Task<OllamaResult> ChatAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, CancellationToken cancellationToken)
-        => await ChatCoreAsync(messages, temperatureOverride, null, cancellationToken).ConfigureAwait(false);
+        => await ChatCoreAsync(messages, temperatureOverride, null, null, cancellationToken).ConfigureAwait(false);
 
     public async Task<OllamaResult> ChatWithToolsAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, IReadOnlyList<InternalToolDefinition> tools, CancellationToken cancellationToken)
-        => await ChatCoreAsync(messages, temperatureOverride, tools, cancellationToken).ConfigureAwait(false);
+        => await ChatCoreAsync(messages, temperatureOverride, tools, null, cancellationToken).ConfigureAwait(false);
+
+    public async Task<OllamaResult> ChatStructuredAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, JsonElement format, CancellationToken cancellationToken)
+        => await ChatCoreAsync(messages, temperatureOverride, null, format, cancellationToken).ConfigureAwait(false);
 
     public async Task<bool?> SupportsVisionAsync(CancellationToken cancellationToken)
     {
@@ -42,7 +45,7 @@ public sealed class OllamaClient : IOllamaClient
         catch (HttpRequestException) { return null; }
     }
 
-    private async Task<OllamaResult> ChatCoreAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, IReadOnlyList<InternalToolDefinition>? tools, CancellationToken cancellationToken)
+    private async Task<OllamaResult> ChatCoreAsync(IReadOnlyList<OllamaMessage> messages, double? temperatureOverride, IReadOnlyList<InternalToolDefinition>? tools, JsonElement? format, CancellationToken cancellationToken)
     {
         Dictionary<string, JsonElement> options = _settings.Options.ToDictionary(static pair => pair.Key, static pair => pair.Value, StringComparer.Ordinal);
         if (temperatureOverride is not null) options["temperature"] = JsonSerializer.SerializeToElement(temperatureOverride.Value);
@@ -54,7 +57,8 @@ public sealed class OllamaClient : IOllamaClient
             Think = _settings.Think,
             KeepAlive = _settings.KeepAlive,
             Options = options,
-            Tools = tools?.Select(static tool => new OllamaToolDefinition("function", new OllamaFunctionDefinition(tool.Name, tool.Description, tool.Parameters))).ToArray()
+            Tools = tools?.Select(static tool => new OllamaToolDefinition("function", new OllamaFunctionDefinition(tool.Name, tool.Description, tool.Parameters))).ToArray(),
+            Format = format
         };
 
         for (int attempt = 0; ; attempt++)
diff --git a/src/Agent.Core/Ollama/OllamaModels.cs b/src/Agent.Core/Ollama/OllamaModels.cs
index 823a178..f4b3884 100644
--- a/src/Agent.Core/Ollama/OllamaModels.cs
+++ b/src/Agent.Core/Ollama/OllamaModels.cs
@@ -33,6 +33,7 @@ public sealed class OllamaChatRequest
     [JsonPropertyName("keep_alive")] public required string KeepAlive { get; init; }
     [JsonPropertyName("options")] public required IReadOnlyDictionary<string, System.Text.Json.JsonElement> Options { get; init; }
     [JsonPropertyName("tools"), JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)] public IReadOnlyList<OllamaToolDefinition>? Tools { get; init; }
+    [JsonPropertyName("format"), JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)] public JsonElement? Format { get; init; }
 }
 
 public sealed class OllamaChatResponse
diff --git a/src/Agent.Core/Runtime/AgentRuntime.cs b/src/Agent.Core/Runtime/AgentRuntime.cs
index 228ac41..f6bb483 100644
--- a/src/Agent.Core/Runtime/AgentRuntime.cs
+++ b/src/Agent.Core/Runtime/AgentRuntime.cs
@@ -1,3 +1,4 @@
+using System.Text.Json;
 using Agent.Core.Ollama;
 using Agent.Core.Prompts;
 using Agent.Core.Sessions;
@@ -28,12 +29,16 @@ public sealed class AgentRuntime(TaskRegistry registry, IOllamaClient ollama, Ag
             await _tools.BeginTaskAsync(taskId, cancellationToken).ConfigureAwait(false);
             if (task.Images.Count > 0 && await ollama.SupportsVisionAsync(cancellationToken).ConfigureAwait(false) is false)
                 throw new InvalidOperationException(settings.VisionUnsupportedMessage);
+
+            // Progressive Disclosure Stage 2: LLM Skill Selection.
+            IReadOnlyList<AgentSkill> selectedSkills = await SelectSkillsAsync(task.Request, cancellationToken).ConfigureAwait(false);
+
             var messages = PromptComposer.Compose(new PromptContext(
                 FixedPrompt.Load(),
                 settings.UserSystemPrompt,
                 settings.Locale,
                 settings.Skills,
-                [],  // SelectedSkills: populated after LLM skill selection (Progressive Disclosure Stage 2→3).
+                selectedSkills,  // Stage 3: selected skill instructions injected by PromptComposer.
                 settings.SandboxCapabilitySummary,
                 "Current task: " + task.Request,
                 string.Empty,
@@ -134,6 +139,66 @@ public sealed class AgentRuntime(TaskRegistry registry, IOllamaClient ollama, Ag
         }
     }
 
+    private async Task<IReadOnlyList<AgentSkill>> SelectSkillsAsync(string request, CancellationToken cancellationToken)
+    {
+        if (settings.Skills.Count == 0) return [];
+
+        // Build a minimal prompt with skill catalog for the LLM to choose from.
+        string catalog = string.Join("\n", settings.Skills.Select(static s => $"- {s.Name}: {s.Description}"));
+        var selectionMessages = new List<OllamaMessage>
+        {
+            new("system", $"Select skills relevant to the user request. Available skills:\n{catalog}\n\nReturn a JSON object with a 'selected_skills' array containing skill names. Select only relevant skills. If none are relevant, return an empty array."),
+            new("user", request)
+        };
+
+        // JSON Schema for structured output.
+        string schema = """{"type":"object","properties":{"selected_skills":{"type":"array","items":{"type":"string"}}},"required":["selected_skills"]}""";
+        using JsonDocument formatDoc = JsonDocument.Parse(schema);
+
+        OllamaResult result;
+        try
+        {
+            result = await ollama.ChatStructuredAsync(selectionMessages, 0.0, formatDoc.RootElement.Clone(), cancellationToken).ConfigureAwait(false);
+        }
+        catch
+        {
+            // If structured output fails (e.g., model doesn't support it), fall back to no skills.
+            return [];
+        }
+
+        return ParseSelectedSkills(result.Content);
+    }
+
+    private IReadOnlyList<AgentSkill> ParseSelectedSkills(string content)
+    {
+        try
+        {
+            using JsonDocument doc = JsonDocument.Parse(content);
+            if (!doc.RootElement.TryGetProperty("selected_skills", out JsonElement skillsElement)) return [];
+            var selectedNames = new HashSet<string>(StringComparer.Ordinal);
+            foreach (JsonElement item in skillsElement.EnumerateArray())
+            {
+                string? name = item.GetString();
+                if (!string.IsNullOrWhiteSpace(name)) selectedNames.Add(name);
+            }
+            // Validate: only known skills, no duplicates, max 10.
+            var valid = new List<AgentSkill>();
+            foreach (AgentSkill skill in settings.Skills)
+            {
+                if (selectedNames.Contains(skill.Name))
+                {
+                    valid.Add(skill);
+                    if (valid.Count >= 10) break;
+                }
+            }
+            return valid;
+        }
+        catch
+        {
+            return [];
+        }
+    }
+
     private async Task<string?> EndTaskSafelyAsync(Guid taskId, bool success, CancellationToken cancellationToken)
     {
         try