refactor: centralize skills directory constants in skill-discovery.js

Export SKILLS_DIR, CLAUDE_SKILLS_DIR, PI_SKILLS_DIR from skill-discovery.js
instead of repeating join(homedir(), ...) inline across 5 files.

Consumers updated:
- preferences-skills.js: replace 2 inline join(homedir()...) with SKILLS_DIR/CLAUDE_SKILLS_DIR
- skill-health.js: replace 2 inline join(homedir()...) with constants; remove homedir import
- skill-catalog.js: replace 2 inline join(homedir()...) with constants; remove homedir import
- skill-telemetry.js: replace 4 inline join(homedir()...) with constants; remove homedir import

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/resources/extensions/sf/preferences-skills.js

@@ -9,6 +9,7 @@ import { homedir } from "node:os";
 import { isAbsolute, join } from "node:path";
 import { validatePreferences } from "./preferences-validation.js";
 import { sfHome } from "./sf-home.js";
+import { CLAUDE_SKILLS_DIR, SKILLS_DIR } from "./skill-discovery.js";
 /**
  * Get skill search directories in priority order for resolution.
  *
@@ -19,10 +20,10 @@ import { sfHome } from "./sf-home.js";
  */
 export function getSkillSearchDirs(cwd) {
 	const dirs = [
-		{ dir: join(homedir(), ".agents", "skills"), method: "user-skill" },
+		{ dir: SKILLS_DIR, method: "user-skill" },
 		{ dir: join(cwd, ".agents", "skills"), method: "project-skill" },
 		// Claude Code official skill directories
-		{ dir: join(homedir(), ".claude", "skills"), method: "user-skill" },
+		{ dir: CLAUDE_SKILLS_DIR, method: "user-skill" },
 		{ dir: join(cwd, ".claude", "skills"), method: "project-skill" },
 	];
 	// Legacy fallback — read skills from old SF directory only if migration hasn't completed

src/resources/extensions/sf/skill-catalog.js

@@ -13,9 +13,9 @@
  */
 import { execFile } from "node:child_process";
 import { existsSync } from "node:fs";
-import { homedir } from "node:os";
 import { join } from "node:path";
 import { showNextAction } from "../shared/tui.js";
+import { CLAUDE_SKILLS_DIR, SKILLS_DIR } from "./skill-discovery.js";
 // ─── Curated Catalog ──────────────────────────────────────────────────────────
 export const SKILL_CATALOG = [
 	// ── Swift (language-level — any Swift project) ────────────────────────────
@@ -961,8 +961,8 @@ export async function installPacksBatched(packs, onProgress) {
  */
 export function isPackInstalled(pack) {
 	const skillsDirs = [
-		join(homedir(), ".agents", "skills"),
+		SKILLS_DIR,
-		join(homedir(), ".claude", "skills"),
+		CLAUDE_SKILLS_DIR,
 	];
 	return pack.skills.every((name) =>
 		skillsDirs.some((dir) => existsSync(join(dir, name, "SKILL.md"))),

src/resources/extensions/sf/skill-discovery.js

@@ -12,9 +12,9 @@ import { homedir } from "node:os";
 import { join } from "node:path";
 
 /** Skills directories — skills.sh ecosystem + Claude Code official + legacy Pi */
-const SKILLS_DIR = join(homedir(), ".agents", "skills");
+export const SKILLS_DIR = join(homedir(), ".agents", "skills");
-const CLAUDE_SKILLS_DIR = join(homedir(), ".claude", "skills");
+export const CLAUDE_SKILLS_DIR = join(homedir(), ".claude", "skills");
-const PI_SKILLS_DIR = join(homedir(), ".pi", "agent", "skills");
+export const PI_SKILLS_DIR = join(homedir(), ".pi", "agent", "skills");
 /** Snapshot of skill names at autonomous mode start */
 let baselineSkills = null;
 /**

src/resources/extensions/sf/skill-health.js

@@ -13,10 +13,10 @@
  * research identified as critical for skill quality.
  */
 import { existsSync, statSync } from "node:fs";
-import { homedir } from "node:os";
 import { join } from "node:path";
 import { formatCost, formatTokenCount, loadLedgerFromDisk } from "./metrics.js";
 import { detectStaleSkills } from "./skill-telemetry.js";
+import { CLAUDE_SKILLS_DIR, SKILLS_DIR } from "./skill-discovery.js";
 
 // ─── Constants ────────────────────────────────────────────────────────────────
 /** Default staleness threshold in days */
@@ -168,8 +168,8 @@ export function formatSkillDetail(basePath, skillName) {
 	}
 	// Check for SKILL.md existence — search both ecosystem and Claude Code directories
 	const candidatePaths = [
-		join(homedir(), ".agents", "skills", skillName, "SKILL.md"),
+		join(SKILLS_DIR, skillName, "SKILL.md"),
-		join(homedir(), ".claude", "skills", skillName, "SKILL.md"),
+		join(CLAUDE_SKILLS_DIR, skillName, "SKILL.md"),
 	];
 	const skillPath = candidatePaths.find((p) => existsSync(p));
 	if (skillPath) {

src/resources/extensions/sf/skill-telemetry.js

@@ -11,9 +11,9 @@
  *   3. At unit completion, getAndClearSkills() returns the loaded list for metrics
  */
 import { existsSync, readdirSync } from "node:fs";
-import { homedir } from "node:os";
 import { join } from "node:path";
 import { sfHome } from "./sf-home.js";
+import { CLAUDE_SKILLS_DIR, SKILLS_DIR } from "./skill-discovery.js";
 
 // ─── In-memory state ──────────────────────────────────────────────────────────
 /** Skills available in the system prompt for the current unit */
@@ -27,11 +27,9 @@ const activelyLoadedSkills = new Set();
  * Called before each unit starts to establish the baseline for telemetry.
  */
 export function captureAvailableSkills() {
-	const skillsDir = join(homedir(), ".agents", "skills");
-	const claudeSkillsDir = join(homedir(), ".claude", "skills");
 	const legacyDir = join(sfHome(), "agent", "skills");
-	const names = listSkillNames(skillsDir);
+	const names = listSkillNames(SKILLS_DIR);
-	const claudeNames = listSkillNames(claudeSkillsDir);
+	const claudeNames = listSkillNames(CLAUDE_SKILLS_DIR);
 	// Include skills still in the legacy directory only if migration hasn't completed
 	const legacyMigrated = existsSync(join(legacyDir, ".migrated-to-agents"));
 	const legacyNames = legacyMigrated ? [] : listSkillNames(legacyDir);
@@ -101,14 +99,12 @@ export function detectStaleSkills(units, thresholdDays) {
 	const cutoff = Date.now() - thresholdDays * 24 * 60 * 60 * 1000;
 	const stale = [];
 	// Check all installed skills, not just those with usage data
-	const skillsDir = join(homedir(), ".agents", "skills");
-	const claudeSkillsDir = join(homedir(), ".claude", "skills");
 	const legacyDir = join(sfHome(), "agent", "skills");
 	const legacyMigrated = existsSync(join(legacyDir, ".migrated-to-agents"));
 	const legacyNames = legacyMigrated ? [] : listSkillNames(legacyDir);
 	const installedSet = new Set([
-		...listSkillNames(skillsDir),
+		...listSkillNames(SKILLS_DIR),
-		...listSkillNames(claudeSkillsDir),
+		...listSkillNames(CLAUDE_SKILLS_DIR),
 		...legacyNames,
 	]);
 	const installed = [...installedSet];