diff --git a/src/resources/extensions/sf/auto.js b/src/resources/extensions/sf/auto.js
index a668deb6b..2cd3bccd3 100644
--- a/src/resources/extensions/sf/auto.js
+++ b/src/resources/extensions/sf/auto.js
@@ -26,9 +26,9 @@ import {
 	unlinkSync,
 	writeFileSync,
 } from "node:fs";
-import { homedir } from "node:os";
 import { isAbsolute, join } from "node:path";
 import { pathToFileURL } from "node:url";
+import { sfHome } from "./sf-home.js";
 import {
 	clearCmuxSidebar,
 	logCmuxEvent,
@@ -1782,7 +1782,7 @@ export async function startAuto(ctx, pi, base, verboseMode, options) {
 		// Using SF_PKG_ROOT constructs a correct absolute path in both contexts (#3949).
 		const agentDir =
 			process.env.SF_CODING_AGENT_DIR ||
-			join(process.env.SF_HOME || homedir(), ".sf", "agent");
+			join(sfHome(), "agent");
 		const pkgRoot = process.env.SF_PKG_ROOT;
 		const resourceLoaderPath = pkgRoot
 			? pathToFileURL(join(pkgRoot, "dist", "resource-loader.js")).href
diff --git a/src/resources/extensions/sf/commands/handlers/core.js b/src/resources/extensions/sf/commands/handlers/core.js
index 32fe8d773..3c07d61e0 100644
--- a/src/resources/extensions/sf/commands/handlers/core.js
+++ b/src/resources/extensions/sf/commands/handlers/core.js
@@ -29,6 +29,7 @@ import { formattedShortcutPair } from "../../shortcut-defs.js";
 import { deriveState } from "../../state.js";
 import { writeUokDiagnostics } from "../../uok/diagnostic-synthesis.js";
 import { projectRoot } from "../context.js";
+import { sfHome } from "../../sf-home.js";
 export function showHelp(ctx, args = "") {
 	const summaryLines = [
 		"SF — Singularity Forge\n",
@@ -1468,8 +1469,7 @@ async function handleResumeCommand(args, ctx) {
 		// Fallback: show recent SF headless session files
 		const { readdirSync, existsSync } = await import("node:fs");
 		const { join: pathJoin } = await import("node:path");
-		const { homedir } = await import("node:os");
-		const sfDir = pathJoin(homedir(), ".sf");
+		const sfDir = sfHome();
 		const sessDir = pathJoin(sfDir, "sessions");
 		if (!existsSync(sessDir)) {
 			ctx.ui.notify(
diff --git a/src/resources/extensions/sf/key-manager.js b/src/resources/extensions/sf/key-manager.js
index c5007fe8e..88570684f 100644
--- a/src/resources/extensions/sf/key-manager.js
+++ b/src/resources/extensions/sf/key-manager.js
@@ -9,6 +9,7 @@ import { dirname, join } from "node:path";
 import { AuthStorage } from "@singularity-forge/coding-agent";
 import { getErrorMessage } from "./error-utils.js";
 import { isEnvAuthAllowed } from "./provider-env-auth.js";
+import { sfHome } from "./sf-home.js";
 export const PROVIDER_REGISTRY = [
 	// LLM Providers
 	{
@@ -250,8 +251,7 @@ export function describeCredential(cred) {
  * Get the auth.json path.
  */
 export function getAuthPath() {
-	const sfHome = process.env.SF_HOME || join(process.env.HOME ?? "~", ".sf");
-	return join(sfHome, "agent", "auth.json");
+	return join(sfHome(), "agent", "auth.json");
 }
 /**
  * Create an AuthStorage instance for key management.
diff --git a/src/resources/extensions/sf/memory-embeddings.js b/src/resources/extensions/sf/memory-embeddings.js
index dcbb39342..413f4e564 100644
--- a/src/resources/extensions/sf/memory-embeddings.js
+++ b/src/resources/extensions/sf/memory-embeddings.js
@@ -13,7 +13,6 @@
 // pipeline stages soft-degrade and `getRelevantMemoriesRanked` falls back
 // to static (confidence × hit_count) ranking.
 import { existsSync, readFileSync } from "node:fs";
-import { homedir } from "node:os";
 import { join } from "node:path";
 import {
 	_getAdapter,
@@ -22,11 +21,12 @@ import {
 	upsertMemoryEmbedding,
 } from "./sf-db.js";
 import { logWarning } from "./workflow-logger.js";
+import { sfHome } from "./sf-home.js";
 
 /** Read the llm-gateway entry from ~/.sf/agent/auth.json if present. */
 function readGatewayFromAuthJson() {
 	try {
-		const authPath = join(homedir(), ".sf", "agent", "auth.json");
+		const authPath = join(sfHome(), "agent", "auth.json");
 		if (!existsSync(authPath)) return null;
 		const data = JSON.parse(readFileSync(authPath, "utf8"));
 		const entry = data["llm-gateway"];
diff --git a/src/resources/extensions/sf/preferences-models.js b/src/resources/extensions/sf/preferences-models.js
index d3b08e1db..eaff35219 100644
--- a/src/resources/extensions/sf/preferences-models.js
+++ b/src/resources/extensions/sf/preferences-models.js
@@ -10,6 +10,7 @@ import { homedir } from "node:os";
 import { join } from "node:path";
 import { getModels, getProviders } from "@singularity-forge/ai";
 import { selectByBenchmarks } from "./benchmark-selector.js";
+import { sfHome } from "./sf-home.js";
 
 import { defaultRoutingConfig, MODEL_CAPABILITY_TIER } from "./model-router.js";
 import {
@@ -535,7 +536,7 @@ export function resolveDefaultSessionModel(sessionProvider) {
 export function isCustomProvider(provider) {
 	if (!provider) return false;
 	const candidates = [
-		join(homedir(), ".sf", "agent", "models.json"),
+		join(sfHome(), "agent", "models.json"),
 		join(homedir(), ".pi", "agent", "models.json"),
 	];
 	for (const path of candidates) {
diff --git a/src/resources/extensions/sf/preferences-skills.js b/src/resources/extensions/sf/preferences-skills.js
index 5dcd67ae0..ae5c969ec 100644
--- a/src/resources/extensions/sf/preferences-skills.js
+++ b/src/resources/extensions/sf/preferences-skills.js
@@ -8,6 +8,7 @@ import { existsSync, readdirSync, statSync } from "node:fs";
 import { homedir } from "node:os";
 import { isAbsolute, join } from "node:path";
 import { validatePreferences } from "./preferences-validation.js";
+import { sfHome } from "./sf-home.js";
 /**
  * Get skill search directories in priority order for resolution.
  *
@@ -25,7 +26,7 @@ export function getSkillSearchDirs(cwd) {
 		{ dir: join(cwd, ".claude", "skills"), method: "project-skill" },
 	];
 	// Legacy fallback — read skills from old SF directory only if migration hasn't completed
-	const legacyDir = join(homedir(), ".sf", "agent", "skills");
+	const legacyDir = join(sfHome(), "agent", "skills");
 	if (
 		existsSync(legacyDir) &&
 		!existsSync(join(legacyDir, ".migrated-to-agents"))
diff --git a/src/resources/extensions/sf/skill-telemetry.js b/src/resources/extensions/sf/skill-telemetry.js
index ce545fa72..8b077fcd4 100644
--- a/src/resources/extensions/sf/skill-telemetry.js
+++ b/src/resources/extensions/sf/skill-telemetry.js
@@ -13,6 +13,7 @@
 import { existsSync, readdirSync } from "node:fs";
 import { homedir } from "node:os";
 import { join } from "node:path";
+import { sfHome } from "./sf-home.js";
 
 // ─── In-memory state ──────────────────────────────────────────────────────────
 /** Skills available in the system prompt for the current unit */
@@ -28,7 +29,7 @@ const activelyLoadedSkills = new Set();
 export function captureAvailableSkills() {
 	const skillsDir = join(homedir(), ".agents", "skills");
 	const claudeSkillsDir = join(homedir(), ".claude", "skills");
-	const legacyDir = join(homedir(), ".sf", "agent", "skills");
+	const legacyDir = join(sfHome(), "agent", "skills");
 	const names = listSkillNames(skillsDir);
 	const claudeNames = listSkillNames(claudeSkillsDir);
 	// Include skills still in the legacy directory only if migration hasn't completed
@@ -102,7 +103,7 @@ export function detectStaleSkills(units, thresholdDays) {
 	// 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(homedir(), ".sf", "agent", "skills");
+	const legacyDir = join(sfHome(), "agent", "skills");
 	const legacyMigrated = existsSync(join(legacyDir, ".migrated-to-agents"));
 	const legacyNames = legacyMigrated ? [] : listSkillNames(legacyDir);
 	const installedSet = new Set([
diff --git a/src/resources/extensions/sf/ui/color-band.js b/src/resources/extensions/sf/ui/color-band.js
index ec23bd9e5..156b64a35 100644
--- a/src/resources/extensions/sf/ui/color-band.js
+++ b/src/resources/extensions/sf/ui/color-band.js
@@ -4,15 +4,15 @@
  * Displays a colored band in the footer to visually distinguish sessions.
  */
 import * as fs from "node:fs";
-import * as os from "node:os";
 import * as path from "node:path";
+import { sfHome } from "../sf-home.js";
 
 const DEFAULT_CONFIG = {
 	enabledByDefault: true,
 	blockChar: "▁",
 	blockCount: "full",
 };
-const STATE_FILE = path.join(os.homedir(), ".sf", "session-color-state.json");
+const STATE_FILE = path.join(sfHome(), "session-color-state.json");
 const COLOR_PALETTE = [
 	196, 51, 226, 129, 46, 208, 27, 213, 118, 160, 87, 220, 93, 34, 202, 75, 199,
 	154, 124, 45, 214, 135, 40, 166, 69, 205, 190, 88, 80, 228, 97, 28, 172, 63,
diff --git a/src/resources/extensions/sf/ui/marketplace.js b/src/resources/extensions/sf/ui/marketplace.js
index 01a732b85..b0234ed5c 100644
--- a/src/resources/extensions/sf/ui/marketplace.js
+++ b/src/resources/extensions/sf/ui/marketplace.js
@@ -1,6 +1,7 @@
 import { existsSync, readdirSync, readFileSync } from "node:fs";
 import { homedir } from "node:os";
 import { join } from "node:path";
+import { sfHome } from "../sf-home.js";
 import {
 	Key,
 	matchesKey,
@@ -92,7 +93,7 @@ function scanInstalledExtensions(dir, sourceLabel) {
 }
 function buildCatalog() {
 	const installed = scanInstalledExtensions(
-		join(homedir(), ".sf", "agent", "extensions"),
+		join(sfHome(), "agent", "extensions"),
 		"installed",
 	);
 	const piCompat = scanInstalledExtensions(
@@ -317,7 +318,7 @@ export function installExtensionNpm(packageId, displayName) {
 		return;
 	}
 	import("node:child_process").then(({ spawn }) => {
-		const target = join(homedir(), ".sf", "agent", "extensions");
+		const target = join(sfHome(), "agent", "extensions");
 		const proc = spawn("npm", ["install", "--prefix", target, packageId], {
 			stdio: ["ignore", "pipe", "pipe"],
 			detached: false,
diff --git a/src/resources/extensions/sf/ui/prompt-history.js b/src/resources/extensions/sf/ui/prompt-history.js
index 9050eaa04..505775ad3 100644
--- a/src/resources/extensions/sf/ui/prompt-history.js
+++ b/src/resources/extensions/sf/ui/prompt-history.js
@@ -1,5 +1,4 @@
 import { appendFileSync, existsSync, mkdirSync, readFileSync } from "node:fs";
-import { homedir } from "node:os";
 import { dirname, join } from "node:path";
 import {
 	Key,
@@ -7,11 +6,12 @@ import {
 	truncateToWidth,
 	visibleWidth,
 } from "@singularity-forge/tui";
+import { sfHome } from "../sf-home.js";
 
 const LIMIT = 20;
 const SCAN_LINE_LIMIT = 2000;
 function promptHistoryPath() {
-	return join(homedir(), ".sf", "agent", "prompt-history.jsonl");
+	return join(sfHome(), "agent", "prompt-history.jsonl");
 }
 function isEnvTruthy(value) {
 	return ["1", "true", "TRUE", "yes", "YES"].includes(String(value ?? ""));
diff --git a/src/resources/extensions/sf/ui/usage-bar.js b/src/resources/extensions/sf/ui/usage-bar.js
index 002f5fd1b..7862c15b7 100644
--- a/src/resources/extensions/sf/ui/usage-bar.js
+++ b/src/resources/extensions/sf/ui/usage-bar.js
@@ -19,12 +19,13 @@ import {
 	setupUser,
 } from "@google/gemini-cli-core";
 import { visibleWidth } from "@singularity-forge/tui";
+import { sfHome } from "../sf-home.js";
 
 // ============================================================================
 // Auth helper
 // ============================================================================
 function loadAuthJson() {
-	const sfAuthPath = path.join(os.homedir(), ".sf", "agent", "auth.json");
+	const sfAuthPath = path.join(sfHome(), "agent", "auth.json");
 	try {
 		if (fs.existsSync(sfAuthPath)) {
 			return JSON.parse(fs.readFileSync(sfAuthPath, "utf-8"));