fix(tui): required space after python prompt sigil

Treat shell-style leading variables such as $HOME as normal chat text instead of Python eval input. Keep local Python shortcuts available through explicit $ <code> and $$ <code> prefixes.\n\nFixes #2944

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed TUI prompts beginning with shell-style variables such as `$HOME` being misrouted to Python eval; Python shortcuts now require `$ <code>` or `$$ <code>`. ([#2944](https://github.com/can1357/oh-my-pi/issues/2944))
+
 ## [16.0.6] - 2026-06-18
 
 ### Added

packages/coding-agent/src/modes/controllers/input-controller.ts

@@ -44,6 +44,26 @@ function hasPasteText(value: unknown): value is PasteTarget {
 	return typeof value === "object" && value !== null && typeof (value as PasteTarget).pasteText === "function";
 }
 
+function pythonCommandPrefixLength(trimmedText: string): 0 | 1 | 2 {
+	if (trimmedText.charCodeAt(0) !== 36 /* $ */) return 0;
+	if (trimmedText.charCodeAt(1) === 123 /* { */) return 0;
+
+	const prefixLength = trimmedText.charCodeAt(1) === 36 /* $ */ ? 2 : 1;
+	const next = trimmedText.charCodeAt(prefixLength);
+	if (Number.isNaN(next)) return prefixLength;
+	return next === 32 || next === 9 || next === 10 || next === 13 ? prefixLength : 0;
+}
+
+function parsePythonCommandInput(text: string): { code: string; isExcluded: boolean } | undefined {
+	const trimmed = text.trimStart();
+	const prefixLength = pythonCommandPrefixLength(trimmed);
+	if (prefixLength === 0) return undefined;
+	return {
+		code: trimmed.slice(prefixLength).trim(),
+		isExcluded: prefixLength === 2,
+	};
+}
+
 /** Wrap pasted text in `<attachment>` tags so the model treats it as one quoted block. */
 function wrapPasteInAttachmentBlock(content: string): string {
 	return `<attachment>\n${content}\n</attachment>`;
@@ -381,8 +401,8 @@ export class InputController {
 			const wasBashMode = this.ctx.isBashMode;
 			const wasPythonMode = this.ctx.isPythonMode;
 			const trimmed = text.trimStart();
-			this.ctx.isBashMode = text.trimStart().startsWith("!");
-			this.ctx.isPythonMode = trimmed.startsWith("$") && !trimmed.startsWith("${");
+			this.ctx.isBashMode = trimmed.startsWith("!");
+			this.ctx.isPythonMode = pythonCommandPrefixLength(trimmed) > 0;
 			if (wasBashMode !== this.ctx.isBashMode || wasPythonMode !== this.ctx.isPythonMode) {
 				this.ctx.updateEditorBorderColor();
 			}
@@ -550,7 +570,7 @@ export class InputController {
 					this.ctx.editor.setText("");
 					return;
 				}
-				if (text.startsWith("!") || text.startsWith("$")) {
+				if (text.startsWith("!") || parsePythonCommandInput(text)) {
 					this.ctx.showStatus("Local execution is host-only during a collab session");
 					this.ctx.editor.setText("");
 					return;
@@ -598,10 +618,11 @@ export class InputController {
 				}
 			}
 
-			// Handle python command ($ for normal, $$ for excluded from context)
-			if (text.startsWith("$")) {
-				const isExcluded = text.startsWith("$$");
-				const code = isExcluded ? text.slice(2).trim() : text.slice(1).trim();
+			// Handle python command (`$ <code>` for normal, `$$ <code>` for excluded from context).
+			// Shell-style variables such as `$HOME` are normal prose unless a space follows the sigil.
+			const pythonCommand = parsePythonCommandInput(text);
+			if (pythonCommand) {
+				const { code, isExcluded } = pythonCommand;
 				if (code) {
 					if (this.ctx.session.isEvalRunning) {
 						this.ctx.showWarning("A Python execution is already running. Press Esc to cancel it first.");
@@ -768,7 +789,7 @@ export class InputController {
 			}
 			return;
 		}
-		if (text.startsWith("/") || text.startsWith("!") || text.startsWith("$")) {
+		if (text.startsWith("/") || text.startsWith("!") || parsePythonCommandInput(text)) {
 			this.ctx.showStatus("Commands run in the main session — press ←← to return first");
 			return; // editor text not cleared: Editor does not auto-clear on submit
 		}

packages/coding-agent/test/input-controller-python-prefix.test.ts

@@ -0,0 +1,130 @@
+import { describe, expect, it, vi } from "bun:test";
+import { InputController } from "@oh-my-pi/pi-coding-agent/modes/controllers/input-controller";
+import type { InteractiveModeContext } from "@oh-my-pi/pi-coding-agent/modes/types";
+
+type FakeEditor = {
+	onSubmit?: (text: string) => Promise<void>;
+	imageLinks?: readonly (string | undefined)[];
+	setText(text: string): void;
+	getText(): string;
+	addToHistory(text: string): void;
+	setActionKeys(action: string, keys: string[]): void;
+	setCustomKeyHandler(key: string, handler: () => void): void;
+	clearCustomKeyHandlers(): void;
+};
+
+function createContext() {
+	let editorText = "";
+	const submitted: unknown[] = [];
+	const handlePythonCommand = vi.fn(async (_code: string, _isExcluded: boolean) => {});
+	const handleBashCommand = vi.fn(async (_command: string, _isExcluded: boolean) => {});
+	const startPendingSubmission = vi.fn((submission: unknown) => submission);
+	const onInputCallback = vi.fn((submission: unknown) => submitted.push(submission));
+	const prompt = vi.fn(async (_text: string, _options?: unknown) => {});
+
+	const editor: FakeEditor = {
+		setText(text) {
+			editorText = text;
+		},
+		getText() {
+			return editorText;
+		},
+		addToHistory: vi.fn(),
+		setActionKeys: vi.fn(),
+		setCustomKeyHandler: vi.fn(),
+		clearCustomKeyHandlers: vi.fn(),
+	};
+
+	const ctx = {
+		editor: editor as unknown as InteractiveModeContext["editor"],
+		ui: { requestRender: vi.fn() } as unknown as InteractiveModeContext["ui"],
+		session: {
+			isStreaming: false,
+			isCompacting: false,
+			isBashRunning: false,
+			isEvalRunning: false,
+			extensionRunner: undefined,
+			prompt,
+			queuedMessageCount: 0,
+			getQueuedMessages: () => ({ steering: [], followUp: [] }),
+		} as unknown as InteractiveModeContext["session"],
+		sessionManager: { getSessionName: () => "named-session" } as unknown as InteractiveModeContext["sessionManager"],
+		pendingImages: [] as InteractiveModeContext["pendingImages"],
+		pendingImageLinks: [] as InteractiveModeContext["pendingImageLinks"],
+		compactionQueuedMessages: [] as InteractiveModeContext["compactionQueuedMessages"],
+		locallySubmittedUserSignatures: new Set<string>(),
+		onInputCallback,
+		startPendingSubmission,
+		updatePendingMessagesDisplay: vi.fn(),
+		flushPendingBashComponents: vi.fn(),
+		updateEditorBorderColor: vi.fn(),
+		showError: vi.fn(),
+		showWarning: vi.fn(),
+		showStatus: vi.fn(),
+		isBashMode: false,
+		isPythonMode: false,
+		fileSlashCommands: new Set<string>(),
+		isKnownSlashCommand: () => false,
+		handlePythonCommand,
+		handleBashCommand,
+		withLocalSubmission: async (_text: string, fn: () => Promise<unknown>) => fn(),
+	} as unknown as InteractiveModeContext;
+
+	return {
+		ctx,
+		editor,
+		handlePythonCommand,
+		onInputCallback,
+		startPendingSubmission,
+		submitted,
+	};
+}
+
+describe("InputController Python prompt prefix", () => {
+	it("submits leading shell-variable prose as a normal prompt", async () => {
+		const { ctx, editor, handlePythonCommand, onInputCallback, startPendingSubmission, submitted } = createContext();
+		const controller = new InputController(ctx);
+		controller.setupEditorSubmitHandler();
+
+		await editor.onSubmit?.("$HOME is home");
+
+		expect(handlePythonCommand).not.toHaveBeenCalled();
+		expect(startPendingSubmission).toHaveBeenCalledWith({
+			text: "$HOME is home",
+			images: undefined,
+			imageLinks: undefined,
+			streamingBehavior: "steer",
+		});
+		expect(onInputCallback).toHaveBeenCalledTimes(1);
+		expect(submitted).toEqual([
+			{
+				text: "$HOME is home",
+				images: undefined,
+				imageLinks: undefined,
+				streamingBehavior: "steer",
+			},
+		]);
+	});
+
+	it("keeps space-separated Python shortcuts available", async () => {
+		const { ctx, editor, handlePythonCommand, onInputCallback } = createContext();
+		const controller = new InputController(ctx);
+		controller.setupEditorSubmitHandler();
+
+		await editor.onSubmit?.("$ print(1)");
+
+		expect(handlePythonCommand).toHaveBeenCalledWith("print(1)", false);
+		expect(onInputCallback).not.toHaveBeenCalled();
+	});
+
+	it("keeps excluded Python shortcuts space-separated too", async () => {
+		const { ctx, editor, handlePythonCommand, onInputCallback } = createContext();
+		const controller = new InputController(ctx);
+		controller.setupEditorSubmitHandler();
+
+		await editor.onSubmit?.("$$ print(1)");
+
+		expect(handlePythonCommand).toHaveBeenCalledWith("print(1)", true);
+		expect(onInputCallback).not.toHaveBeenCalled();
+	});
+});