Add managed Git skill plugin state

src/Netclaw.Cli.Tests/Doctor/ConfigSchemaDoctorCheckTests.cs

@@ -481,6 +481,37 @@ await File.WriteAllTextAsync(paths.NetclawConfigPath,
         Assert.Equal(DoctorSeverity.Pass, result.Severity);
     }
 
+    [Fact]
+    public async Task ReturnsPass_WhenGitSkillPluginSourceIsValid()
+    {
+        var basePath = CreateTempBasePath();
+        var paths = new NetclawPaths(basePath);
+        paths.EnsureDirectoriesExist();
+
+        await File.WriteAllTextAsync(paths.NetclawConfigPath,
+            """
+            {
+              "configVersion": 1,
+              "SkillFeeds": {
+                "Plugins": [{
+                  "Name": "dotnet-skills",
+                  "Repository": "Aaronontheweb/dotnet-skills",
+                  "Format": "codex",
+                  "ReferenceKind": "Commit",
+                  "Reference": "13e26d39ed01d97ea592235d041304d289f4ba07",
+                  "Enabled": true,
+                  "TimeoutSeconds": 60
+                }]
+              }
+            }
+            """, TestContext.Current.CancellationToken);
+
+        var check = new ConfigSchemaDoctorCheck(paths);
+        var result = await check.RunAsync(TestContext.Current.CancellationToken);
+
+        Assert.Equal(DoctorSeverity.Pass, result.Severity);
+    }
+
     [Fact]
     public async Task ReturnsPass_WhenToolsAudienceProfilesAndMcpCapabilityValid()
     {

src/Netclaw.Cli.Tests/Tui/Config/SkillSourcesConfigViewModelTests.cs

@@ -4,6 +4,7 @@
 // </copyright>
 // -----------------------------------------------------------------------
 using Microsoft.Extensions.Configuration;
+using System.Text.Json;
 using Netclaw.Cli.Tui.Config;
 using Netclaw.Configuration;
 using Netclaw.Configuration.Secrets;
@@ -66,6 +67,49 @@ public async Task Rescan_all_does_not_badge_disabled_remote_servers()
         Assert.DoesNotContain("advertised", remoteRow.Detail, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public void Toggle_feed_preserves_managed_Git_plugins()
+    {
+        File.WriteAllText(
+            _paths.NetclawConfigPath,
+            """
+            {"configVersion":1,"SkillFeeds":{"Feeds":[{"Name":"custom-feed","Url":"https://feed.example.test","Enabled":true}],"Plugins":[{"Name":"dotnet-skills","Repository":"owner/repository","Format":"codex","Subdirectory":"packages/plugin","ReferenceKind":"Branch","Reference":"main","Enabled":true,"TimeoutSeconds":90}]}}
+            """);
+        using var vm = new SkillSourcesConfigViewModel(_paths, new FakeSkillFeedProbe(true));
+
+        vm.CommitToggleEnabled(new SkillSourceActionTarget(SkillSourceKind.RemoteSkillServer, "custom-feed"));
+
+        using var document = JsonDocument.Parse(File.ReadAllText(_paths.NetclawConfigPath));
+        var section = document.RootElement.GetProperty("SkillFeeds");
+        Assert.False(section.GetProperty("Feeds")[0].GetProperty("Enabled").GetBoolean());
+        var plugin = Assert.Single(section.GetProperty("Plugins").EnumerateArray());
+        Assert.Equal("owner/repository", plugin.GetProperty("Repository").GetString());
+        Assert.Equal("packages/plugin", plugin.GetProperty("Subdirectory").GetString());
+        Assert.Equal("Branch", plugin.GetProperty("ReferenceKind").GetString());
+        Assert.Equal(90, plugin.GetProperty("TimeoutSeconds").GetInt32());
+    }
+
+    [Fact]
+    public void Remove_last_feed_preserves_managed_Git_plugins()
+    {
+        File.WriteAllText(
+            _paths.NetclawConfigPath,
+            """
+            {"configVersion":1,"SkillFeeds":{"Feeds":[{"Name":"custom-feed","Url":"https://feed.example.test","Enabled":true}],"Plugins":[{"Name":"dotnet-skills","Repository":"owner/repository","Format":"codex","ReferenceKind":"Commit","Reference":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","Enabled":false,"TimeoutSeconds":60}]}}
+            """);
+        using var vm = new SkillSourcesConfigViewModel(_paths, new FakeSkillFeedProbe(true));
+
+        vm.CommitRemoveSource(new SkillSourceActionTarget(SkillSourceKind.RemoteSkillServer, "custom-feed"));
+
+        using var document = JsonDocument.Parse(File.ReadAllText(_paths.NetclawConfigPath));
+        var section = document.RootElement.GetProperty("SkillFeeds");
+        Assert.Empty(section.GetProperty("Feeds").EnumerateArray());
+        var plugin = Assert.Single(section.GetProperty("Plugins").EnumerateArray());
+        Assert.Equal("dotnet-skills", plugin.GetProperty("Name").GetString());
+        Assert.Equal("Commit", plugin.GetProperty("ReferenceKind").GetString());
+        Assert.False(plugin.GetProperty("Enabled").GetBoolean());
+    }
+
     [Fact]
     public async Task Rescan_all_invalidates_a_cached_count_when_the_server_is_disabled()
     {

src/Netclaw.Cli/Tui/Config/SkillSourcesConfigViewModel.cs

@@ -2263,7 +2263,7 @@ private bool SaveExternalConfig(ExternalSkillsConfig external)
     private bool SaveSkillFeedsConfig(SkillFeedsConfigDocument feeds)
         => TryEditConfig(root =>
         {
-            if (feeds.Feeds.Count == 0)
+            if (feeds.Feeds.Count == 0 && feeds.Plugins.Count == 0)
                 root.Remove("SkillFeeds");
             else
                 root["SkillFeeds"] = BuildSkillFeedsSection(feeds);
@@ -2522,6 +2522,24 @@ private static Dictionary<string, object> BuildSkillFeedsSection(SkillFeedsConfi
 
                 return (object)item;
             }).ToArray(),
+            ["Plugins"] = config.Plugins.Select(static plugin =>
+            {
+                var item = new Dictionary<string, object>
+                {
+                    ["Name"] = plugin.Name,
+                    ["Repository"] = plugin.Repository,
+                    ["Format"] = plugin.Format,
+                    ["ReferenceKind"] = plugin.ReferenceKind.ToString(),
+                    ["Reference"] = plugin.Reference,
+                    ["Enabled"] = plugin.Enabled,
+                    ["TimeoutSeconds"] = plugin.TimeoutSeconds,
+                };
+
+                if (!string.IsNullOrWhiteSpace(plugin.Subdirectory))
+                    item["Subdirectory"] = plugin.Subdirectory;
+
+                return (object)item;
+            }).ToArray(),
         };
 
     private static LocalSkillScanDisplay ScanLocalSkills(string directory, bool allowSymlinks)
@@ -2617,6 +2635,8 @@ private sealed class SkillFeedsConfigDocument
         public int SyncIntervalMinutes { get; set; } = 60;
 
         public List<SkillFeedConfigEntry> Feeds { get; set; } = [];
+
+        public List<GitSkillPluginSource> Plugins { get; set; } = [];
     }
 
     private sealed class SkillFeedConfigEntry

src/Netclaw.Configuration.Tests/GitSkillPluginSourceValidatorTests.cs

@@ -0,0 +1,120 @@
+// -----------------------------------------------------------------------
+// <copyright file="GitSkillPluginSourceValidatorTests.cs" company="Petabridge, LLC">
+//      Copyright (C) 2026 - 2026 Petabridge, LLC <https://petabridge.com>
+// </copyright>
+// -----------------------------------------------------------------------
+using Xunit;
+
+namespace Netclaw.Configuration.Tests;
+
+public sealed class GitSkillPluginSourceValidatorTests
+{
+    [Theory]
+    [InlineData("Aaronontheweb/dotnet-skills", "Aaronontheweb/dotnet-skills")]
+    [InlineData("https://github.com/Aaronontheweb/dotnet-skills", "Aaronontheweb/dotnet-skills")]
+    [InlineData("https://github.com/Aaronontheweb/dotnet-skills.git", "Aaronontheweb/dotnet-skills")]
+    public void Repository_normalization_accepts_public_GitHub_forms(string value, string expected)
+    {
+        Assert.True(GitSkillPluginSourceValidator.TryNormalizeRepository(value, out var actual, out _));
+        Assert.Equal(expected, actual);
+    }
+
+    [Theory]
+    [InlineData("http://github.com/owner/repo")]
+    [InlineData("https://user@github.com/owner/repo")]
+    [InlineData("https://github.com:8443/owner/repo")]
+    [InlineData("https://gitlab.com/owner/repo")]
+    [InlineData("https://github.com/owner/repo?token=secret")]
+    [InlineData("https://github.com/owner/repo#readme")]
+    [InlineData("--upload-pack=bad")]
+    public void Repository_normalization_rejects_unsafe_transport_forms(string value)
+    {
+        Assert.False(GitSkillPluginSourceValidator.TryNormalizeRepository(value, out _, out _));
+    }
+
+    [Fact]
+    public void Source_validation_requires_a_full_commit_identity()
+    {
+        var source = Source();
+        source.ReferenceKind = GitSkillPluginReferenceKind.Commit;
+        source.Reference = "abc123";
+
+        Assert.False(GitSkillPluginSourceValidator.TryValidateSource(source, out var error));
+        Assert.Contains("full 40-character", error);
+    }
+
+    [Fact]
+    public void Fingerprint_changes_for_each_source_semantic()
+    {
+        var source = Source();
+        var original = GitSkillPluginSourceValidator.Fingerprint(source);
+
+        source.Subdirectory = "plugin";
+
+        Assert.NotEqual(original, GitSkillPluginSourceValidator.Fingerprint(source));
+    }
+
+    [Fact]
+    public void Collection_validation_rejects_duplicate_names()
+    {
+        var first = Source();
+        var second = Source();
+        second.Repository = "owner/other";
+
+        Assert.False(GitSkillPluginSourceValidator.TryValidateSources([first, second], out var error));
+        Assert.Contains("occurs more than once", error);
+    }
+
+    [Fact]
+    public void Collection_validation_rejects_more_than_twenty_sources()
+    {
+        var sources = Enumerable.Range(0, 21).Select(index =>
+        {
+            var source = Source();
+            source.Name = $"source-{index}";
+            return source;
+        }).ToArray();
+
+        Assert.False(GitSkillPluginSourceValidator.TryValidateSources(sources, out var error));
+        Assert.Contains("No more than 20", error);
+    }
+
+    [Theory]
+    [InlineData("./plugin/")]
+    [InlineData("/plugin")]
+    [InlineData("plugin/../other")]
+    public void Source_validation_rejects_a_noncanonical_subdirectory(string subdirectory)
+    {
+        var source = Source();
+        source.Subdirectory = subdirectory;
+
+        Assert.False(GitSkillPluginSourceValidator.TryValidateSource(source, out _));
+    }
+
+    [Theory]
+    [InlineData("owner/.")]
+    [InlineData("owner/..")]
+    [InlineData("./repository")]
+    public void Repository_normalization_rejects_dot_components(string repository)
+    {
+        Assert.False(GitSkillPluginSourceValidator.TryNormalizeRepository(repository, out _, out _));
+    }
+
+    [Fact]
+    public void Source_validation_rejects_an_unknown_reference_type()
+    {
+        var source = Source();
+        source.ReferenceKind = (GitSkillPluginReferenceKind)99;
+
+        Assert.False(GitSkillPluginSourceValidator.TryValidateSource(source, out _));
+    }
+
+    private static GitSkillPluginSource Source() => new()
+    {
+        Name = "dotnet-skills",
+        Repository = "Aaronontheweb/dotnet-skills",
+        Format = "codex",
+        ReferenceKind = GitSkillPluginReferenceKind.Branch,
+        Reference = "main",
+    };
+}

src/Netclaw.Configuration/NetclawPaths.cs

@@ -42,6 +42,15 @@ public sealed class NetclawPaths
     // ── Server feed skills (from private skill-server instances) ──
     public string ServerFeedsDirectory => Path.Combine(SkillsDirectory, ".server-feeds");
 
+    // Managed plugin commits remain immutable while the registry can reference them.
+    public string ManagedGitSkillsDirectory => Path.Combine(SkillsDirectory, ".git-plugins");
+
+    public string ManagedGitSkillDirectory(string sourceName)
+        => Path.Combine(ManagedGitSkillsDirectory, sourceName);
+
+    public string ManagedGitSkillCommitDirectory(string sourceName, string commit)
+        => Path.Combine(ManagedGitSkillDirectory(sourceName), "commits", commit);
+
     public string ServerFeedDirectory(string feedName)
         => Path.Combine(ServerFeedsDirectory, feedName);
 
@@ -185,6 +194,7 @@ private IEnumerable<string> StandardDirectories()
         yield return SkillsDirectory;
         yield return SystemSkillsDirectory;
         yield return ServerFeedsDirectory;
+        yield return ManagedGitSkillsDirectory;
         yield return ProjectsDirectory;
         yield return ClientDirectory;
         yield return EnvironmentDirectory;

src/Netclaw.Configuration/OperationalAlert.cs

@@ -42,6 +42,7 @@ public enum AlertType
     // New values stay at the end so prior ordinal values remain stable.
     ReminderScheduleFailed,
     ChannelReconnected,
+    SkillPluginSecurityRejected,
 }
 
 /// <summary>

src/Netclaw.Configuration/Schemas/netclaw-config.v1.schema.json

@@ -627,6 +627,26 @@
             "required": ["Name", "Url"],
             "additionalProperties": false
           }
+        },
+        "Plugins": {
+          "type": "array",
+          "maxItems": 20,
+          "description": "Managed public GitHub skill plugins.",
+          "items": {
+            "type": "object",
+            "properties": {
+              "Name": { "type": "string", "pattern": "^[a-z0-9]+(?:-[a-z0-9]+)*$", "maxLength": 64 },
+              "Repository": { "type": "string", "pattern": "^[A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+$" },
+              "Format": { "type": "string", "enum": ["codex"], "default": "codex" },
+              "Subdirectory": { "type": ["string", "null"], "minLength": 1, "maxLength": 512 },
+              "ReferenceKind": { "type": "string", "enum": ["Branch", "Commit"] },
+              "Reference": { "type": "string", "minLength": 1, "maxLength": 256 },
+              "Enabled": { "type": "boolean", "default": true },
+              "TimeoutSeconds": { "type": "integer", "minimum": 1, "maximum": 300, "default": 60 }
+            },
+            "required": ["Name", "Repository", "Format", "ReferenceKind", "Reference"],
+            "additionalProperties": false
+          }
         }
       },
       "additionalProperties": false