feat(skills): implement dynamic skills registry with caching

This commit introduces a skills registry system that fetches available
skills from a remote registry instead of hardcoding them. The system
includes network fetching with fallback to local cache and bundled
files, plus UI integration to display and refresh skills dynamically.
This enables easier skill discovery and updates without requiring code
changes.

Author: zzxwill

.gitignore

@@ -1 +1,3 @@
 agentx
+dist/
+checksums.txt

internal/skills/registry.go

@@ -0,0 +1,171 @@
+package skills
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// DefaultSkillsRegistryURL is the default URL for the skills registry
+const DefaultSkillsRegistryURL = "https://raw.githubusercontent.com/agentsdance/agentskills/master/skills.json"
+
+// RegistrySkill represents a skill entry in the registry
+type RegistrySkill struct {
+	Name        string `json:"name"`
+	Description string `json:"description"`
+	Author      string `json:"author,omitempty"`
+	License     string `json:"license,omitempty"`
+	Source      string `json:"source"`
+}
+
+// SkillsRegistry represents the skills registry
+type SkillsRegistry struct {
+	Version string          `json:"version"`
+	Skills  []RegistrySkill `json:"skills"`
+}
+
+// FetchSkillsRegistry fetches the skills registry from the default URL
+func FetchSkillsRegistry() ([]RegistrySkill, error) {
+	return FetchSkillsRegistryFromURL(DefaultSkillsRegistryURL)
+}
+
+// FetchSkillsRegistryFromURL fetches the skills registry from a specific URL
+func FetchSkillsRegistryFromURL(registryURL string) ([]RegistrySkill, error) {
+	client := &http.Client{
+		Timeout: 10 * time.Second,
+	}
+
+	resp, err := client.Get(registryURL)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch skills registry: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("skills registry returned status %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read skills registry response: %w", err)
+	}
+
+	var registry SkillsRegistry
+	if err := json.Unmarshal(body, &registry); err != nil {
+		return nil, fmt.Errorf("failed to parse skills registry: %w", err)
+	}
+
+	// Cache the registry locally
+	if err := cacheSkillsRegistry(body); err != nil {
+		// Non-fatal, just log if needed
+	}
+
+	return registry.Skills, nil
+}
+
+// GetCachedSkillsRegistry returns the cached skills registry if available
+func GetCachedSkillsRegistry() ([]RegistrySkill, error) {
+	cachePath, err := getSkillsRegistryCachePath()
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := os.ReadFile(cachePath)
+	if err != nil {
+		return nil, err
+	}
+
+	var registry SkillsRegistry
+	if err := json.Unmarshal(data, &registry); err != nil {
+		return nil, err
+	}
+
+	return registry.Skills, nil
+}
+
+// FetchSkillsRegistryWithFallback tries to fetch from network, falls back to cache, then to local file
+func FetchSkillsRegistryWithFallback() ([]RegistrySkill, error) {
+	skills, err := FetchSkillsRegistry()
+	if err == nil && len(skills) > 0 {
+		return skills, nil
+	}
+
+	// Try cached version
+	cached, cacheErr := GetCachedSkillsRegistry()
+	if cacheErr == nil && len(cached) > 0 {
+		return cached, nil
+	}
+
+	// Try local bundled registry file (for development)
+	local, localErr := GetLocalSkillsRegistry()
+	if localErr == nil && len(local) > 0 {
+		return local, nil
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	return skills, nil
+}
+
+// GetLocalSkillsRegistry reads the skills registry from the local bundled file
+func GetLocalSkillsRegistry() ([]RegistrySkill, error) {
+	// Try common locations for the registry file
+	paths := []string{
+		"registry/skills.json",                       // Current working directory
+		"./registry/skills.json",                     // Explicit current directory
+		filepath.Join("..", "registry/skills.json"), // Parent directory
+	}
+
+	// Also try relative to executable
+	if exe, err := os.Executable(); err == nil {
+		exeDir := filepath.Dir(exe)
+		paths = append(paths, filepath.Join(exeDir, "registry", "skills.json"))
+		paths = append(paths, filepath.Join(exeDir, "..", "registry", "skills.json"))
+	}
+
+	for _, path := range paths {
+		data, err := os.ReadFile(path)
+		if err != nil {
+			continue
+		}
+
+		var registry SkillsRegistry
+		if err := json.Unmarshal(data, &registry); err != nil {
+			continue
+		}
+
+		return registry.Skills, nil
+	}
+
+	return nil, fmt.Errorf("local skills registry not found")
+}
+
+// cacheSkillsRegistry saves the skills registry data to local cache
+func cacheSkillsRegistry(data []byte) error {
+	cachePath, err := getSkillsRegistryCachePath()
+	if err != nil {
+		return err
+	}
+
+	// Ensure cache directory exists
+	cacheDir := filepath.Dir(cachePath)
+	if err := os.MkdirAll(cacheDir, 0755); err != nil {
+		return err
+	}
+
+	return os.WriteFile(cachePath, data, 0644)
+}
+
+// getSkillsRegistryCachePath returns the path to the cached skills registry
+func getSkillsRegistryCachePath() (string, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(home, ".agentx", "cache", "skills-registry.json"), nil
+}

ui/views/skills.go

@@ -7,6 +7,7 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 	"github.com/agentsdance/agentx/internal/agent"
+	"github.com/agentsdance/agentx/internal/skills"
 	"github.com/agentsdance/agentx/ui/components"
 	"github.com/agentsdance/agentx/ui/theme"
 )
@@ -18,14 +19,39 @@ type AvailableSkill struct {
 	Source      string // GitHub tree URL or repo#fragment
 }
 
-// Available skills from anthropics/skills repository
-var AvailableSkills = []AvailableSkill{
-	{Name: "frontend-design", Description: "Production-grade UI design", Source: "https://github.com/anthropics/skills/tree/main/skills/frontend-design"},
-	{Name: "mcp-builder", Description: "Build MCP servers", Source: "https://github.com/anthropics/skills/tree/main/skills/mcp-builder"},
-	{Name: "pdf", Description: "PDF document handling", Source: "https://github.com/anthropics/skills/tree/main/skills/pdf"},
-	{Name: "docx", Description: "Word document handling", Source: "https://github.com/anthropics/skills/tree/main/skills/docx"},
-	{Name: "xlsx", Description: "Excel spreadsheet handling", Source: "https://github.com/anthropics/skills/tree/main/skills/xlsx"},
-	{Name: "pptx", Description: "PowerPoint handling", Source: "https://github.com/anthropics/skills/tree/main/skills/pptx"},
+// AvailableSkills is the list of skills from the registry
+var AvailableSkills []AvailableSkill
+
+// InitAvailableSkills fetches skills from the registry
+func InitAvailableSkills() {
+	registrySkills, err := skills.FetchSkillsRegistryWithFallback()
+	if err != nil {
+		// Use empty list if fetch fails
+		AvailableSkills = []AvailableSkill{}
+		return
+	}
+
+	AvailableSkills = make([]AvailableSkill, len(registrySkills))
+	for i, s := range registrySkills {
+		// Convert source to installation URL
+		source := s.Source
+		if source == "local" {
+			// For local skills in agentsdance/agentskills repo
+			source = fmt.Sprintf("https://github.com/agentsdance/agentskills/tree/master/skills/%s", s.Name)
+		}
+
+		// Truncate description for display
+		desc := s.Description
+		if len(desc) > 40 {
+			desc = desc[:37] + "..."
+		}
+
+		AvailableSkills[i] = AvailableSkill{
+			Name:        s.Name,
+			Description: desc,
+			Source:      source,
+		}
+	}
 }
 
 // AgentSkillStatus represents an agent's skill installation status
@@ -49,6 +75,9 @@ type SkillsView struct {
 
 // NewSkillsView creates a new skills view
 func NewSkillsView() *SkillsView {
+	// Initialize available skills from registry
+	InitAvailableSkills()
+
 	agents := agent.GetAllAgents()
 	statuses := make([]AgentSkillStatus, len(agents))
 
@@ -111,12 +140,22 @@ func (v *SkillsView) Update(msg tea.Msg) (View, tea.Cmd) {
 		case "c":
 			v.refreshStatus()
 			v.message = "Status refreshed"
+		case "R":
+			// Force refresh skills from registry
+			InitAvailableSkills()
+			v.refreshStatus()
+			v.message = fmt.Sprintf("Refreshed %d skills from registry", len(AvailableSkills))
 		}
 	}
 	return v, nil
 }
 
 func (v *SkillsView) installSelected() {
+	if len(AvailableSkills) == 0 {
+		v.message = "No skills available"
+		return
+	}
+
 	status := &v.agents[v.cursorCol]
 	agentName := status.Agent.Name()
 	skill := AvailableSkills[v.cursorRow]
@@ -140,6 +179,11 @@ func (v *SkillsView) installSelected() {
 }
 
 func (v *SkillsView) installAllForSelectedSkill() {
+	if len(AvailableSkills) == 0 {
+		v.message = "No skills available"
+		return
+	}
+
 	installed := 0
 	skill := AvailableSkills[v.cursorRow]
 
@@ -158,6 +202,11 @@ func (v *SkillsView) installAllForSelectedSkill() {
 }
 
 func (v *SkillsView) removeSelected() {
+	if len(AvailableSkills) == 0 {
+		v.message = "No skills available"
+		return
+	}
+
 	status := &v.agents[v.cursorCol]
 	agentName := status.Agent.Name()
 	skill := AvailableSkills[v.cursorRow]
@@ -225,8 +274,14 @@ func (v *SkillsView) View() string {
 	b.WriteString(borderStyle.Render("  " + strings.Repeat("─", 70)))
 	b.WriteString("\n")
 
+	// Check if skills are available
+	if len(AvailableSkills) == 0 {
+		b.WriteString("\n  No skills available. Press 'R' to refresh from registry.\n")
+		return b.String()
+	}
+
 	// Column headers (Agent names)
-	b.WriteString("                  ")
+	b.WriteString("                              ")
 	for i, status := range v.agents {
 		style := colHeaderStyle
 		if i == v.cursorCol {
@@ -251,12 +306,12 @@ func (v *SkillsView) View() string {
 			row.WriteString("  ")
 		}
 
-		// Skill name
+		// Skill name - width 28 characters for long names
 		name := skill.Name
-		if len(name) > 14 {
-			name = name[:14]
+		if len(name) > 28 {
+			name = name[:28]
 		}
-		row.WriteString(fmt.Sprintf("%-14s", name))
+		row.WriteString(fmt.Sprintf("%-28s", name))
 
 		// Status for each agent
 		for agentIdx, status := range v.agents {
@@ -316,6 +371,7 @@ func (v *SkillsView) ShortHelp() []components.FooterAction {
 		{Key: "←→", Label: "select agent"},
 		{Key: "↑↓", Label: "select skill"},
 		{Key: "c", Label: "check"},
+		{Key: "R", Label: "refresh"},
 		{Key: "q", Label: "quit"},
 	}
 }