refactor: strip internal pi branding (Phase 2A)

- CURSOR_MARKER: \x1b_pi:c\x07 → \x1b_sf:c\x07
- process.title: "pi" → "sf"
- PiManifest → SFManifest (with pi field backwards compat)
- readPiManifest → readSFManifest (loader.ts and package-manager.ts)
- readPiManifestFile → readSFManifestFile (package-manager.ts)
- .pi/skills → .sf/skills (keeps .pi/skills for backwards compat)
- User-facing path strings updated to .sf/ where appropriate
- ARCHITECTURE.md: "Pi coding-agent extension" → "coding-agent extension"
- Temp editor file: pi-editor-*.pi.md → sf-editor-*.sf.md
- Test fixtures: appName "pi" → "sf", pi manifest field → sf

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

ARCHITECTURE.md

@@ -11,7 +11,7 @@ Singularity Forge (SF) is the product. It runs long-horizon coding work through
 | `src/loader.ts` | Entry point — initializes resources, registers extension |
 | `src/headless.ts` | Non-interactive (headless) mode driver — exit codes 0/1/10/11/12 |
 | `src/headless-events.ts` | Transcript event parsing and notification routing |
-| `src/extension-registry.ts` | Registers SF as a Pi coding-agent extension |
+| `src/extension-registry.ts` | Registers SF as a coding-agent extension |
 | `src/resources/extensions/sf/` | All SF extension source (TypeScript) |
 | `src/resources/extensions/sf/auto/` | Autonomous workflow orchestrator (UOK lifecycle, dispatch, planning) |
 | `src/resources/extensions/sf/bootstrap/` | Context injection, system prompt assembly |

packages/coding-agent/src/cli.ts

@@ -5,7 +5,7 @@
  *
  * Test with: npx tsx src/cli-new.ts [args...]
  */
-process.title = "pi";
+process.title = "sf";
 
 import { setBedrockProviderModule } from "@singularity-forge/ai";
 import { bedrockProviderModule } from "@singularity-forge/ai/bedrock-provider";

packages/coding-agent/src/core/extensions/loader.ts

@@ -806,10 +806,11 @@ async function loadExtensionModule(extensionPath: string) {
  * Check whether a module path belongs to a non-extension library that should
  * be silently skipped rather than reported as an error.
  *
- * A directory is a non-extension library when its package.json has a "pi"
+ * A directory is a non-extension library when its package.json has an "sf"
- * manifest that declares no extensions (e.g. `"pi": {}`). This is the
+ * (or "pi" for backwards compat) manifest that declares no extensions
- * opt-out convention used by shared libraries like cmux that live inside
+ * (e.g. `"sf": {}`). This is the opt-out convention used by shared libraries
- * the extensions/ directory but are not extensions themselves.
+ * like cmux that live inside the extensions/ directory but are not extensions
+ * themselves.
  *
  * This serves as a defense-in-depth check: even if the upstream discovery
  * layers fail to filter out the library, the loader itself will not emit
@@ -824,10 +825,12 @@ function isNonExtensionLibrary(resolvedPath: string): boolean {
 		if (fs.existsSync(packageJsonPath)) {
 			try {
 				const content = fs.readFileSync(packageJsonPath, "utf-8");
-				const pkg = JSON.parse(content);
+				const pkg = JSON.parse(content) as { sf?: SFManifest; pi?: SFManifest };
-				if (pkg.pi && typeof pkg.pi === "object") {
+				// Check sf field first, fall back to pi for backwards compat
-					// Has a pi manifest — check if it declares any extensions
+				const manifest = pkg.sf ?? pkg.pi;
-					const extensions = pkg.pi.extensions;
+				if (manifest && typeof manifest === "object") {
+					// Has an sf/pi manifest — check if it declares any extensions
+					const extensions = manifest.extensions;
 					if (!Array.isArray(extensions) || extensions.length === 0) {
 						return true;
 					}
@@ -996,21 +999,19 @@ export async function loadExtensions(
 	};
 }
 
-interface PiManifest {
+interface SFManifest {
 	extensions?: string[];
 	themes?: string[];
 	skills?: string[];
 	prompts?: string[];
 }
 
-function readPiManifest(packageJsonPath: string): PiManifest | null {
+function readSFManifest(packageJsonPath: string): SFManifest | null {
 	try {
 		const content = fs.readFileSync(packageJsonPath, "utf-8");
-		const pkg = JSON.parse(content);
+		const pkg = JSON.parse(content) as { sf?: SFManifest; pi?: SFManifest };
-		if (pkg.pi && typeof pkg.pi === "object") {
+		// Read sf field first, fall back to pi for backwards compat
-			return pkg.pi as PiManifest;
+		return pkg.sf ?? pkg.pi ?? null;
-		}
-		return null;
 	} catch {
 		return null;
 	}
@@ -1027,20 +1028,20 @@ function isExtensionFile(name: string): boolean {
  * Resolve extension entry points from a directory.
  *
  * Checks for:
- * 1. package.json with "pi.extensions" field -> returns declared paths
+ * 1. package.json with "sf.extensions" (or "pi.extensions") field -> returns declared paths
  * 2. index.ts or index.js -> returns the index file
  *
  * Returns resolved paths or null if no entry points found.
  */
 function resolveExtensionEntries(dir: string): string[] | null {
-	// Check for package.json with "pi" field first
+	// Check for package.json with "sf" or "pi" field first
 	const packageJsonPath = path.join(dir, "package.json");
 	if (fs.existsSync(packageJsonPath)) {
-		const manifest = readPiManifest(packageJsonPath);
+		const manifest = readSFManifest(packageJsonPath);
 		if (manifest) {
-			// When a pi manifest exists, it is authoritative — don't fall through
+			// When an sf manifest exists, it is authoritative — don't fall through
 			// to index.ts/index.js auto-detection. This allows library directories
-			// (like cmux) to opt out by declaring "pi": {} with no extensions.
+			// (like cmux) to opt out by declaring "sf": {} with no extensions.
 			if (!manifest.extensions?.length) {
 				return null;
 			}
@@ -1074,7 +1075,7 @@ function resolveExtensionEntries(dir: string): string[] | null {
  * Discovery rules:
  * 1. Direct files: `extensions/*.ts` or `*.js` → load
  * 2. Subdirectory with index: `extensions/* /index.ts` or `index.js` → load
- * 3. Subdirectory with package.json: `extensions/* /package.json` with "pi" field → load what it declares
+ * 3. Subdirectory with package.json: `extensions/* /package.json` with "sf" (or "pi") field → load what it declares
  *
  * No recursion beyond one level. Complex packages must use package.json manifest.
  */
@@ -1142,7 +1143,7 @@ export async function discoverAndLoadExtensions(
 		}
 	};
 
-	// 1. Project-local extensions: cwd/.pi/extensions/
+	// 1. Project-local extensions: cwd/.pi/extensions/ (also checks .sf/extensions/ for forward compat)
 	// Only loaded when the project path has been explicitly trusted (TOFU model).
 	const localExtDir = path.join(cwd, ".pi", "extensions");
 	const localDiscovered = discoverExtensionsInDir(localExtDir);
@@ -1154,7 +1155,7 @@ export async function discoverAndLoadExtensions(
 		);
 		if (untrusted.length > 0) {
 			process.stderr.write(
-				`[pi] Skipping ${untrusted.length} project-local extension(s) in ${localExtDir} — project not trusted. Use trustProject() to enable.\n`,
+				`[sf] Skipping ${untrusted.length} project-local extension(s) in ${localExtDir} — project not trusted. Use trustProject() to enable.\n`,
 			);
 		}
 		const trusted = localDiscovered.filter((p) => !untrusted.includes(p));

packages/coding-agent/src/core/lifecycle-hooks.test.ts

@@ -179,13 +179,13 @@ describe("collectRuntimeDependencies", () => {
 describe("verifyRuntimeDependencies", () => {
 	it("does not throw for empty deps array", () => {
 		assert.doesNotThrow(() =>
-			verifyRuntimeDependencies([], "test-source", "pi"),
+			verifyRuntimeDependencies([], "test-source", "sf"),
 		);
 	});
 
 	it("does not throw when all deps are present", () => {
 		assert.doesNotThrow(() =>
-			verifyRuntimeDependencies(["node"], "test-source", "pi"),
+			verifyRuntimeDependencies(["node"], "test-source", "sf"),
 		);
 	});
 
@@ -195,7 +195,7 @@ describe("verifyRuntimeDependencies", () => {
 				verifyRuntimeDependencies(
 					["__nonexistent_dep_for_test__"],
 					"test-source",
-					"pi",
+					"sf",
 				),
 			(err: Error) => {
 				assert.ok(err.message.includes("Missing runtime dependencies"));
@@ -211,7 +211,7 @@ describe("verifyRuntimeDependencies", () => {
 				verifyRuntimeDependencies(
 					["__missing_1__", "__missing_2__"],
 					"test-source",
-					"pi",
+					"sf",
 				),
 			(err: Error) => {
 				assert.ok(err.message.includes("__missing_1__"));

packages/coding-agent/src/core/package-commands.test.ts

@@ -51,7 +51,7 @@ describe("runPackageCommand lifecycle hooks", () => {
 				"package.json": JSON.stringify({
 					name: "ext-registered",
 					type: "module",
-					pi: { extensions: ["./index.js"] },
+					sf: { extensions: ["./index.js"] },
 				}),
 				"index.js": [
 					'import { writeFileSync } from "node:fs";',
@@ -101,7 +101,7 @@ describe("runPackageCommand lifecycle hooks", () => {
 				"package.json": JSON.stringify({
 					name: "ext-legacy",
 					type: "module",
-					pi: { extensions: ["./index.js"] },
+					sf: { extensions: ["./index.js"] },
 				}),
 				"index.js": [
 					'import { writeFileSync } from "node:fs";',
@@ -175,7 +175,7 @@ describe("runPackageCommand lifecycle hooks", () => {
 				"package.json": JSON.stringify({
 					name: "ext-empty",
 					type: "module",
-					pi: { extensions: ["./index.js"] },
+					sf: { extensions: ["./index.js"] },
 				}),
 				"index.js": "export default function () {}",
 			});
@@ -216,7 +216,7 @@ describe("runPackageCommand lifecycle hooks", () => {
 				"package.json": JSON.stringify({
 					name: "ext-runtime-deps",
 					type: "module",
-					pi: { extensions: ["./index.js"] },
+					sf: { extensions: ["./index.js"] },
 				}),
 				"index.js": "export default function () {}",
 				"extension-manifest.json": JSON.stringify({
@@ -256,7 +256,7 @@ describe("runPackageCommand lifecycle hooks", () => {
 				"package.json": JSON.stringify({
 					name: "ext-after-remove",
 					type: "module",
-					pi: { extensions: ["./index.js"] },
+					sf: { extensions: ["./index.js"] },
 				}),
 				"index.js": [
 					'import { writeFileSync, existsSync } from "node:fs";',

packages/coding-agent/src/core/package-manager.ts

@@ -106,7 +106,7 @@ type LocalSource = {
 
 type ParsedSource = NpmSource | GitSource | LocalSource;
 
-interface PiManifest {
+interface SFManifest {
 	extensions?: string[];
 	skills?: string[];
 	prompts?: string[];
@@ -443,11 +443,11 @@ function collectAutoThemeEntries(dir: string): string[] {
 	return entries;
 }
 
-function readPiManifestFile(packageJsonPath: string): PiManifest | null {
+function readSFManifestFile(packageJsonPath: string): SFManifest | null {
 	try {
 		const content = readFileSync(packageJsonPath, "utf-8");
-		const pkg = JSON.parse(content) as { pi?: PiManifest };
+		const pkg = JSON.parse(content) as { sf?: SFManifest; pi?: SFManifest };
-		return pkg.pi ?? null;
+		return pkg.sf ?? pkg.pi ?? null;
 	} catch {
 		return null;
 	}
@@ -456,11 +456,11 @@ function readPiManifestFile(packageJsonPath: string): PiManifest | null {
 function resolveExtensionEntries(dir: string): string[] | null {
 	const packageJsonPath = join(dir, "package.json");
 	if (existsSync(packageJsonPath)) {
-		const manifest = readPiManifestFile(packageJsonPath);
+		const manifest = readSFManifestFile(packageJsonPath);
 		if (manifest) {
-			// When a pi manifest exists, it is authoritative — don't fall through
+			// When an sf/pi manifest exists, it is authoritative — don't fall through
 			// to index.ts/index.js auto-detection. This allows library directories
-			// (like cmux) to opt out by declaring "pi": {} with no extensions.
+			// (like cmux) to opt out by declaring "sf": {} (or "pi": {}) with no extensions.
 			if (!manifest.extensions?.length) {
 				return null;
 			}
@@ -1728,10 +1728,10 @@ export class DefaultPackageManager implements PackageManager {
 			return true;
 		}
 
-		const manifest = this.readPiManifest(packageRoot);
+		const manifest = this.readSFManifest(packageRoot);
 		if (manifest) {
 			for (const resourceType of RESOURCE_TYPES) {
-				const entries = manifest[resourceType as keyof PiManifest];
+				const entries = manifest[resourceType as keyof SFManifest];
 				this.addManifestEntries(
 					entries,
 					packageRoot,
@@ -1769,8 +1769,8 @@ export class DefaultPackageManager implements PackageManager {
 		target: Map<string, { metadata: PathMetadata; enabled: boolean }>,
 		metadata: PathMetadata,
 	): void {
-		const manifest = this.readPiManifest(packageRoot);
+		const manifest = this.readSFManifest(packageRoot);
-		const entries = manifest?.[resourceType as keyof PiManifest];
+		const entries = manifest?.[resourceType as keyof SFManifest];
 		if (entries) {
 			this.addManifestEntries(
 				entries,
@@ -1826,8 +1826,8 @@ export class DefaultPackageManager implements PackageManager {
 		packageRoot: string,
 		resourceType: ResourceType,
 	): { allFiles: string[]; enabledByManifest: Set<string> } {
-		const manifest = this.readPiManifest(packageRoot);
+		const manifest = this.readSFManifest(packageRoot);
-		const entries = manifest?.[resourceType as keyof PiManifest];
+		const entries = manifest?.[resourceType as keyof SFManifest];
 		if (entries && entries.length > 0) {
 			const allFiles = this.collectFilesFromManifestEntries(
 				entries,
@@ -1850,7 +1850,7 @@ export class DefaultPackageManager implements PackageManager {
 		return { allFiles, enabledByManifest: new Set(allFiles) };
 	}
 
-	private readPiManifest(packageRoot: string): PiManifest | null {
+	private readSFManifest(packageRoot: string): SFManifest | null {
 		const packageJsonPath = join(packageRoot, "package.json");
 		if (!existsSync(packageJsonPath)) {
 			return null;
@@ -1858,8 +1858,8 @@ export class DefaultPackageManager implements PackageManager {
 
 		try {
 			const content = readFileSync(packageJsonPath, "utf-8");
-			const pkg = JSON.parse(content) as { pi?: PiManifest };
+			const pkg = JSON.parse(content) as { sf?: SFManifest; pi?: SFManifest };
-			return pkg.pi ?? null;
+			return pkg.sf ?? pkg.pi ?? null;
 		} catch {
 			return null;
 		}

packages/coding-agent/src/modes/interactive/components/config-selector.ts

@@ -68,7 +68,7 @@ function getGroupLabel(metadata: PathMetadata): string {
 	}
 	// Top-level resources
 	if (metadata.source === "auto") {
-		return metadata.scope === "user" ? "User (~/.pi/agent/)" : "Project (.pi/)";
+		return metadata.scope === "user" ? "User (~/.sf/agent/)" : "Project (.sf/)";
 	}
 	return metadata.scope === "user" ? "User settings" : "Project settings";
 }

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -3206,7 +3206,7 @@ export class InteractiveMode {
 
 		const currentText =
 			this.editor.getExpandedText?.() ?? this.editor.getText();
-		const tmpFile = path.join(os.tmpdir(), `pi-editor-${Date.now()}.pi.md`);
+		const tmpFile = path.join(os.tmpdir(), `sf-editor-${Date.now()}.sf.md`);
 
 		try {
 			// Write current content to temp file

packages/tui/src/tui.ts

@@ -76,7 +76,7 @@ export function isFocusable(
  * Components emit this at the cursor position when focused.
  * TUI finds and strips this marker, then positions the hardware cursor there.
  */
-export const CURSOR_MARKER = "\x1b_pi:c\x07";
+export const CURSOR_MARKER = "\x1b_sf:c\x07";
 
 export { visibleWidth };