chore: enforce erasable TypeScript syntax

AGENTS.md

@@ -16,6 +16,7 @@
 - Check node_modules for external API type definitions instead of guessing
 - **NEVER use inline imports** - no `await import("./foo.js")`, no `import("pkg").Type` in type positions, no dynamic imports for types. Always use standard top-level imports.
 - NEVER remove or downgrade code to fix type errors from outdated dependencies; upgrade the dependency instead
+- In core source packages (`packages/ai/src`, `packages/agent/src`, `packages/coding-agent/src`), use only erasable TypeScript syntax compatible with Node strip-only mode. Do not use constructor parameter properties, `enum`, `namespace`/`module`, `import =`, `export =`, or other TypeScript constructs that require JavaScript emit. Use explicit fields and constructor assignments instead of parameter properties.
 - Always ask before removing functionality or code that appears to be intentional
 - Do not preserve backward compatibility unless the user explicitly asks for it
 - Never hardcode key checks with, eg. `matchesKey(keyData, "ctrl+x")`. All keybindings must be configurable. Add default to matching object (`DEFAULT_EDITOR_KEYBINDINGS` or `DEFAULT_APP_KEYBINDINGS`)

package.json

@@ -15,7 +15,8 @@
 		"build": "cd packages/tui && npm run build && cd ../ai && npm run build && cd ../agent && npm run build && cd ../coding-agent && npm run build && cd ../web-ui && npm run build",
 		"dev": "concurrently --names \"ai,agent,coding-agent,web-ui,tui\" --prefix-colors \"cyan,yellow,red,green,magenta\" \"cd packages/ai && npm run dev\" \"cd packages/agent && npm run dev\" \"cd packages/coding-agent && npm run dev\" \"cd packages/web-ui && npm run dev\" \"cd packages/tui && npm run dev\"",
 		"dev:tsc": "concurrently --names \"ai,web-ui\" --prefix-colors \"cyan,green\" \"cd packages/ai && npm run dev:tsc\" \"cd packages/web-ui && npm run dev:tsc\"",
-		"check": "biome check --write --error-on-warnings . && tsgo --noEmit && npm run check:browser-smoke && cd packages/web-ui && npm run check",
+		"check": "biome check --write --error-on-warnings . && tsgo --noEmit && npm run check:erasable-types && npm run check:browser-smoke && cd packages/web-ui && npm run check",
+		"check:erasable-types": "tsgo -p packages/ai/tsconfig.build.json --noEmit --erasableSyntaxOnly && tsgo -p packages/agent/tsconfig.build.json --noEmit --erasableSyntaxOnly && tsgo -p packages/coding-agent/tsconfig.build.json --noEmit --erasableSyntaxOnly",
 		"check:browser-smoke": "node scripts/check-browser-smoke.mjs",
 		"profile:tui": "node scripts/profile-coding-agent-node.mjs --mode tui",
 		"profile:rpc": "node scripts/profile-coding-agent-node.mjs --mode rpc",

packages/agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Changed source syntax to avoid TypeScript constructs that require JavaScript emit, keeping the package compatible with Node.js strip-only TypeScript checks.
+
 ### Fixed
 
 - Fixed tool-call preflight to stop preparing sibling tool calls after the run is aborted ([#4276](https://github.com/earendil-works/pi/issues/4276)).

packages/agent/src/agent.ts

@@ -117,8 +117,11 @@ export interface AgentOptions {
 
 class PendingMessageQueue {
 	private messages: AgentMessage[] = [];
+	public mode: QueueMode;
 
-	constructor(public mode: QueueMode) {}
+	constructor(mode: QueueMode) {
+		this.mode = mode;
+	}
 
 	enqueue(message: AgentMessage): void {
 		this.messages.push(message);

packages/agent/src/harness/types.ts

@@ -120,16 +120,16 @@ export type FileErrorCode =
 
 /** Error returned by {@link FileSystem} file operations. */
 export class FileError extends Error {
-	constructor(
-		/** Backend-independent error code. */
-		public code: FileErrorCode,
-		message: string,
-		/** Absolute addressed path associated with the failure, when available. */
-		public path?: string,
-		cause?: Error,
-	) {
+	/** Backend-independent error code. */
+	public code: FileErrorCode;
+	/** Absolute addressed path associated with the failure, when available. */
+	public path?: string;
+
+	constructor(code: FileErrorCode, message: string, path?: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "FileError";
+		this.code = code;
+		this.path = path;
 	}
 }
 
@@ -144,14 +144,13 @@ export type ExecutionErrorCode =
 
 /** Error returned by {@link ExecutionEnv.exec}. */
 export class ExecutionError extends Error {
-	constructor(
-		/** Backend-independent error code. */
-		public code: ExecutionErrorCode,
-		message: string,
-		cause?: Error,
-	) {
+	/** Backend-independent error code. */
+	public code: ExecutionErrorCode;
+
+	constructor(code: ExecutionErrorCode, message: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "ExecutionError";
+		this.code = code;
 	}
 }
 
@@ -160,14 +159,13 @@ export type CompactionErrorCode = "aborted" | "summarization_failed" | "invalid_
 
 /** Error returned by compaction helpers. */
 export class CompactionError extends Error {
-	constructor(
-		/** Backend-independent error code. */
-		public code: CompactionErrorCode,
-		message: string,
-		cause?: Error,
-	) {
+	/** Backend-independent error code. */
+	public code: CompactionErrorCode;
+
+	constructor(code: CompactionErrorCode, message: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "CompactionError";
+		this.code = code;
 	}
 }
 
@@ -176,14 +174,13 @@ export type BranchSummaryErrorCode = "aborted" | "summarization_failed" | "inval
 
 /** Error returned by branch summarization helpers. */
 export class BranchSummaryError extends Error {
-	constructor(
-		/** Backend-independent error code. */
-		public code: BranchSummaryErrorCode,
-		message: string,
-		cause?: Error,
-	) {
+	/** Backend-independent error code. */
+	public code: BranchSummaryErrorCode;
+
+	constructor(code: BranchSummaryErrorCode, message: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "BranchSummaryError";
+		this.code = code;
 	}
 }
 
@@ -197,14 +194,13 @@ export type SessionErrorCode =
 
 /** Error thrown by session storage, repositories, and session tree operations. */
 export class SessionError extends Error {
-	constructor(
-		/** Session subsystem error code. */
-		public code: SessionErrorCode,
-		message: string,
-		cause?: Error,
-	) {
+	/** Session subsystem error code. */
+	public code: SessionErrorCode;
+
+	constructor(code: SessionErrorCode, message: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "SessionError";
+		this.code = code;
 	}
 }
 
@@ -221,13 +217,12 @@ export type AgentHarnessErrorCode =
 
 /** Public AgentHarness failure with a stable top-level classification. */
 export class AgentHarnessError extends Error {
-	constructor(
-		public code: AgentHarnessErrorCode,
-		message: string,
-		cause?: Error,
-	) {
+	public code: AgentHarnessErrorCode;
+
+	constructor(code: AgentHarnessErrorCode, message: string, cause?: Error) {
 		super(message, cause === undefined ? undefined : { cause });
 		this.name = "AgentHarnessError";
+		this.code = code;
 	}
 }
 

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Changed source syntax to avoid TypeScript constructs that require JavaScript emit, keeping the package compatible with Node.js strip-only TypeScript checks.
+
 ### Fixed
 
 - Fixed OpenAI-compatible `streamSimple()` requests to stop sending model-derived default output token caps, avoiding context-window reservation failures on servers such as vLLM while preserving explicit `maxTokens` and required Anthropic `max_tokens` handling ([#4675](https://github.com/earendil-works/pi/issues/4675)).

packages/ai/src/utils/event-stream.ts

@@ -7,11 +7,12 @@ export class EventStream<T, R = T> implements AsyncIterable<T> {
 	private done = false;
 	private finalResultPromise: Promise<R>;
 	private resolveFinalResult!: (result: R) => void;
+	private isComplete: (event: T) => boolean;
+	private extractResult: (event: T) => R;
 
-	constructor(
-		private isComplete: (event: T) => boolean,
-		private extractResult: (event: T) => R,
-	) {
+	constructor(isComplete: (event: T) => boolean, extractResult: (event: T) => R) {
+		this.isComplete = isComplete;
+		this.extractResult = extractResult;
 		this.finalResultPromise = new Promise((resolve) => {
 			this.resolveFinalResult = resolve;
 		});

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Changed source syntax to avoid TypeScript constructs that require JavaScript emit, keeping core sources compatible with Node.js strip-only TypeScript checks.
+
 ### Fixed
 
 - Fixed the system prompt to tell models to resolve pi docs and examples under the absolute package paths before reading topic-specific relative references ([#4752](https://github.com/earendil-works/pi/issues/4752)).

packages/coding-agent/src/core/agent-session-runtime.ts

@@ -67,14 +67,25 @@ function extractUserMessageText(content: string | Array<{ type: string; text?: s
 export class AgentSessionRuntime {
 	private rebindSession?: (session: AgentSession) => Promise<void>;
 	private beforeSessionInvalidate?: () => void;
+	private _session: AgentSession;
+	private _services: AgentSessionServices;
+	private readonly createRuntime: CreateAgentSessionRuntimeFactory;
+	private _diagnostics: AgentSessionRuntimeDiagnostic[];
+	private _modelFallbackMessage?: string;
 
 	constructor(
-		private _session: AgentSession,
-		private _services: AgentSessionServices,
-		private readonly createRuntime: CreateAgentSessionRuntimeFactory,
-		private _diagnostics: AgentSessionRuntimeDiagnostic[] = [],
-		private _modelFallbackMessage?: string,
-	) {}
+		_session: AgentSession,
+		_services: AgentSessionServices,
+		createRuntime: CreateAgentSessionRuntimeFactory,
+		_diagnostics: AgentSessionRuntimeDiagnostic[] = [],
+		_modelFallbackMessage?: string,
+	) {
+		this._session = _session;
+		this._services = _services;
+		this.createRuntime = createRuntime;
+		this._diagnostics = _diagnostics;
+		this._modelFallbackMessage = _modelFallbackMessage;
+	}
 
 	get services(): AgentSessionServices {
 		return this._services;

packages/coding-agent/src/core/auth-storage.ts

@@ -50,7 +50,11 @@ export interface AuthStorageBackend {
 }
 
 export class FileAuthStorageBackend implements AuthStorageBackend {
-	constructor(private authPath: string = join(getAgentDir(), "auth.json")) {}
+	private authPath: string;
+
+	constructor(authPath: string = join(getAgentDir(), "auth.json")) {
+		this.authPath = authPath;
+	}
 
 	private ensureParentDir(): void {
 		const dir = dirname(this.authPath);
@@ -194,8 +198,10 @@ export class AuthStorage {
 	private fallbackResolver?: (provider: string) => string | undefined;
 	private loadError: Error | null = null;
 	private errors: Error[] = [];
+	private storage: AuthStorageBackend;
 
-	private constructor(private storage: AuthStorageBackend) {
+	private constructor(storage: AuthStorageBackend) {
+		this.storage = storage;
 		this.reload();
 	}
 

packages/coding-agent/src/core/model-registry.ts

@@ -334,11 +334,12 @@ export class ModelRegistry {
 	private modelRequestHeaders: Map<string, Record<string, string>> = new Map();
 	private registeredProviders: Map<string, ProviderConfigInput> = new Map();
 	private loadError: string | undefined = undefined;
+	readonly authStorage: AuthStorage;
+	private modelsJsonPath: string | undefined;
 
-	private constructor(
-		readonly authStorage: AuthStorage,
-		private modelsJsonPath: string | undefined,
-	) {
+	private constructor(authStorage: AuthStorage, modelsJsonPath: string | undefined) {
+		this.authStorage = authStorage;
+		this.modelsJsonPath = modelsJsonPath;
 		this.loadModels();
 	}
 

packages/coding-agent/src/modes/interactive/components/countdown-timer.ts

@@ -7,13 +7,14 @@ import type { TUI } from "@earendil-works/pi-tui";
 export class CountdownTimer {
 	private intervalId: ReturnType<typeof setInterval> | undefined;
 	private remainingSeconds: number;
+	private tui: TUI | undefined;
+	private onTick: (seconds: number) => void;
+	private onExpire: () => void;
 
-	constructor(
-		timeoutMs: number,
-		private tui: TUI | undefined,
-		private onTick: (seconds: number) => void,
-		private onExpire: () => void,
-	) {
+	constructor(timeoutMs: number, tui: TUI | undefined, onTick: (seconds: number) => void, onExpire: () => void) {
+		this.tui = tui;
+		this.onTick = onTick;
+		this.onExpire = onExpire;
 		this.remainingSeconds = Math.ceil(timeoutMs / 1000);
 		this.onTick(this.remainingSeconds);
 

packages/coding-agent/src/modes/interactive/components/footer.ts

@@ -32,11 +32,13 @@ function formatTokens(count: number): string {
  */
 export class FooterComponent implements Component {
 	private autoCompactEnabled = true;
+	private session: AgentSession;
+	private footerData: ReadonlyFooterDataProvider;
 
-	constructor(
-		private session: AgentSession,
-		private footerData: ReadonlyFooterDataProvider,
-	) {}
+	constructor(session: AgentSession, footerData: ReadonlyFooterDataProvider) {
+		this.session = session;
+		this.footerData = footerData;
+	}
 
 	setSession(session: AgentSession): void {
 		this.session = session;

packages/coding-agent/src/modes/interactive/components/login-dialog.ts

@@ -15,6 +15,7 @@ export class LoginDialogComponent extends Container implements Focusable {
 	private abortController = new AbortController();
 	private inputResolver?: (value: string) => void;
 	private inputRejecter?: (error: Error) => void;
+	private onComplete: (success: boolean, message?: string) => void;
 
 	// Focusable implementation - propagate to input for IME cursor positioning
 	private _focused = false;
@@ -29,12 +30,13 @@ export class LoginDialogComponent extends Container implements Focusable {
 	constructor(
 		tui: TUI,
 		providerId: string,
-		private onComplete: (success: boolean, message?: string) => void,
+		onComplete: (success: boolean, message?: string) => void,
 		providerNameOverride?: string,
 		titleOverride?: string,
 	) {
 		super();
 		this.tui = tui;
+		this.onComplete = onComplete;
 
 		const providerInfo = getOAuthProviders().find((p) => p.id === providerId);
 		const providerName = providerNameOverride || providerInfo?.name || providerId;

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

@@ -1056,7 +1056,11 @@ class TreeList implements Component {
 
 /** Component that displays the current search query */
 class SearchLine implements Component {
-	constructor(private treeList: TreeList) {}
+	private treeList: TreeList;
+
+	constructor(treeList: TreeList) {
+		this.treeList = treeList;
+	}
 
 	invalidate(): void {}
 

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

@@ -147,14 +147,19 @@ function isExpandable(obj: unknown): obj is Expandable {
 }
 
 class ExpandableText extends Text implements Expandable {
+	private readonly getCollapsedText: () => string;
+	private readonly getExpandedText: () => string;
+
 	constructor(
-		private readonly getCollapsedText: () => string,
-		private readonly getExpandedText: () => string,
+		getCollapsedText: () => string,
+		getExpandedText: () => string,
 		expanded = false,
 		paddingX = 0,
 		paddingY = 0,
 	) {
 		super(expanded ? getExpandedText() : getCollapsedText(), paddingX, paddingY);
+		this.getCollapsedText = getCollapsedText;
+		this.getExpandedText = getExpandedText;
 	}
 
 	setExpanded(expanded: boolean): void {
@@ -334,6 +339,8 @@ export class InteractiveMode {
 	// Custom header from extension (undefined = use built-in header)
 	private customHeader: (Component & { dispose?(): void }) | undefined = undefined;
 
+	private options: InteractiveModeOptions;
+
 	// Convenience accessors
 	private get session(): AgentSession {
 		return this.runtimeHost.session;
@@ -348,11 +355,9 @@ export class InteractiveMode {
 		return this.session.settingsManager;
 	}
 
-	constructor(
-		runtimeHost: AgentSessionRuntime,
-		private options: InteractiveModeOptions = {},
-	) {
+	constructor(runtimeHost: AgentSessionRuntime, options: InteractiveModeOptions = {}) {
 		this.runtimeHost = runtimeHost;
+		this.options = options;
 		this.runtimeHost.setBeforeSessionInvalidate(() => {
 			this.resetExtensionUI();
 		});

packages/coding-agent/src/modes/rpc/rpc-client.ts

@@ -59,8 +59,11 @@ export class RpcClient {
 		new Map();
 	private requestId = 0;
 	private stderr = "";
+	private options: RpcClientOptions;
 
-	constructor(private options: RpcClientOptions = {}) {}
+	constructor(options: RpcClientOptions = {}) {
+		this.options = options;
+	}
 
 	/**
 	 * Start the RPC agent process.