1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
using System.Text.RegularExpressions;
using Agent.Core.Skills;
using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;
namespace Agent.App.Configuration;
public static class SkillLoader
{
private static readonly Regex NamePattern = new("^[a-z0-9]([a-z0-9-]*[a-z0-9])?$", RegexOptions.Compiled);
public static IReadOnlyList<AgentSkill> Load(string directory)
{
if (!Directory.Exists(directory)) return [];
var skills = new List<AgentSkill>();
var names = new HashSet<string>(StringComparer.Ordinal);
foreach (string child in Directory.EnumerateDirectories(directory, "*", SearchOption.TopDirectoryOnly))
{
var info = new DirectoryInfo(child);
if ((info.Attributes & FileAttributes.ReparsePoint) != 0) continue;
string skillMd = Path.Combine(info.FullName, "SKILL.md");
if (!File.Exists(skillMd)) continue;
string dirName = info.Name;
string content = File.ReadAllText(skillMd);
var (frontmatter, body) = SplitFrontmatter(content);
if (frontmatter is null)
throw new SkillLoadException($"Skill '{dirName}': SKILL.md is missing YAML frontmatter.");
SkillFrontmatter fm = ParseFrontmatter(frontmatter);
ValidateSkill(dirName, fm, names);
skills.Add(new AgentSkill(
RootPath: info.FullName,
Name: fm.Name,
Description: fm.Description,
Instructions: body.Trim(),
License: fm.License,
Compatibility: fm.Compatibility,
Metadata: fm.Metadata,
AllowedTools: fm.AllowedTools));
}
return skills;
}
private static void ValidateSkill(string dirName, SkillFrontmatter fm, HashSet<string> names)
{
if (string.IsNullOrWhiteSpace(fm.Name))
throw new SkillLoadException($"Skill '{dirName}': name is required.");
if (fm.Name.Length < 1 || fm.Name.Length > 64)
throw new SkillLoadException($"Skill '{dirName}': name must be 1-64 characters.");
if (!NamePattern.IsMatch(fm.Name))
throw new SkillLoadException($"Skill '{dirName}': name must be lowercase alphanumeric with hyphens.");
if (!fm.Name.Equals(dirName, StringComparison.Ordinal))
throw new SkillLoadException($"Skill '{dirName}': name '{fm.Name}' does not match directory name.");
if (string.IsNullOrWhiteSpace(fm.Description))
throw new SkillLoadException($"Skill '{dirName}': description is required.");
if (fm.Description.Length > 1024)
throw new SkillLoadException($"Skill '{dirName}': description must be 1-1024 characters.");
if (!names.Add(fm.Name))
throw new SkillLoadException($"Duplicate skill name '{fm.Name}'.");
}
private static (string? Frontmatter, string Body) SplitFrontmatter(string content)
{
if (!content.StartsWith("---", StringComparison.Ordinal)) return (null, content);
int end = content.IndexOf("\n---", 3, StringComparison.Ordinal);
if (end < 0) return (null, content);
string frontmatter = content[3..end].Trim();
int bodyStart = end + 4;
if (bodyStart < content.Length && content[bodyStart] == '\r') bodyStart++;
if (bodyStart < content.Length && content[bodyStart] == '\n') bodyStart++;
string body = bodyStart < content.Length ? content[bodyStart..] : string.Empty;
return (frontmatter, body);
}
private static SkillFrontmatter ParseFrontmatter(string yaml)
{
try
{
var deserializer = new DeserializerBuilder()
.WithNamingConvention(UnderscoredNamingConvention.Instance)
.Build();
return deserializer.Deserialize<SkillFrontmatter>(yaml);
}
catch (Exception ex)
{
throw new SkillLoadException($"Malformed YAML frontmatter: {ex.Message}");
}
}
private sealed class SkillFrontmatter
{
public string Name { get; set; } = "";
public string Description { get; set; } = "";
public string? License { get; set; }
public string? Compatibility { get; set; }
public Dictionary<string, string>? Metadata { get; set; }
public string? AllowedTools { get; set; }
}
}
public sealed class SkillLoadException(string message) : Exception(message);
|
