Clarify send_to_terminal input semantics and throttle duplicate background input-needed steering

[Copilot]

This addresses review feedback on PR #308855: the send_to_terminal tool contract did not reflect empty-input (Enter) behavior, and background run_in_terminal input-needed detection could emit repeated steering requests.

• Tool contract alignment (sendToTerminalTool)

  • Updated modelDescription to describe command as terminal input text (not only shell commands).
  • Updated schema docs to explicitly allow empty/whitespace command to send only Enter for interactive prompts.

• Background steering dedupe/throttle (runInTerminalTool)

  • Added background onDidDetectInputNeeded steering notifications.
  • Added duplicate suppression for repeated input-needed signals with unchanged output within a throttle window.
  • Introduced a named constant for throttle duration (INPUT_NEEDED_NOTIFICATION_THROTTLE_MS).

• Focused test coverage

  • Updated sendToTerminalTool tests to assert the new contract wording.
  • Added a runInTerminalTool test validating:
    • duplicate rapid input-needed events are suppressed, and
    • a changed prompt/output triggers a new steering notification.

const isDuplicate =
	currentOutput === lastInputNeededOutput &&
	now - lastInputNeededNotificationTime < INPUT_NEEDED_NOTIFICATION_THROTTLE_MS;
if (isDuplicate) {
	return;
}

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[Copilot]

Pull request overview

This PR aligns the terminal chat agent tools’ documented contracts with actual interactive behavior, and reduces repeated “input needed” steering chatter for background run_in_terminal executions.

Changes:

• Updated send_to_terminal tool documentation to clarify that command is arbitrary terminal input and may be empty/whitespace to send only Enter.
• Added background input-needed steering notifications to run_in_terminal, with dedupe/throttling to suppress rapid duplicates when output hasn’t changed.
• Expanded unit tests to validate the updated contract wording and the new dedupe behavior.

Show a summary per file

File	Description
src/vs/workbench/contrib/terminalContrib/chatAgentTools/test/electron-browser/runInTerminalTool.test.ts	Adds coverage for deduping background input-needed steering requests and extends chat service stubbing to capture steering calls.
src/vs/workbench/contrib/terminalContrib/chatAgentTools/test/browser/sendToTerminalTool.test.ts	Updates assertions to reflect the clarified send_to_terminal contract wording.
src/vs/workbench/contrib/terminalContrib/chatAgentTools/browser/tools/sendToTerminalTool.ts	Updates tool modelDescription and schema docs to describe empty/whitespace input semantics.
src/vs/workbench/contrib/terminalContrib/chatAgentTools/browser/tools/runInTerminalTool.ts	Introduces throttling/deduping of background input-needed steering notifications.

Copilot's findings

• Files reviewed: 4/4 changed files
• Comments generated: 1

[Copilot]

This test mutates the private static RunInTerminalTool._activeExecutions map via .set(...) but never removes the entry. Because the map is static, this can leak state across tests and potentially affect later tests (or accumulate over time) within the same test run. Add cleanup (e.g. delete(termId)/clear() in a try/finally, or register a stub execution that can be removed via RunInTerminalTool.removeExecution).

Suggested change

	(runInTerminalTool.constructor as unknown as { _activeExecutions: Map<string, { getOutput(): string }> })._activeExecutions.set(termId, {
	getOutput: () => output,
	});
	(runInTerminalTool as unknown as { _registerCompletionNotification: (terminal: ITerminalInstance, termId: string, session: URI, commandName: string, outputMonitor: { onDidDetectInputNeeded: Event<void>; continueMonitoringAsync: () => void; dispose: () => void }) => void })
	._registerCompletionNotification(terminalInstance, termId, sessionResource, 'npm init', outputMonitor);
	inputNeededEmitter.fire();
	inputNeededEmitter.fire();
	strictEqual(capturedSteeringRequests.length, 1, 'Expected duplicate rapid input-needed events to be suppressed');
	output = 'Confirm (y/N):';
	inputNeededEmitter.fire();
	strictEqual(capturedSteeringRequests.length, 2, 'Expected a changed prompt to trigger a new notification');
	const activeExecutions = (runInTerminalTool.constructor as unknown as { _activeExecutions: Map<string, { getOutput(): string }> })._activeExecutions;
	activeExecutions.set(termId, {
	getOutput: () => output,
	});
	try {
	(runInTerminalTool as unknown as { _registerCompletionNotification: (terminal: ITerminalInstance, termId: string, session: URI, commandName: string, outputMonitor: { onDidDetectInputNeeded: Event<void>; continueMonitoringAsync: () => void; dispose: () => void }) => void })
	._registerCompletionNotification(terminalInstance, termId, sessionResource, 'npm init', outputMonitor);
	inputNeededEmitter.fire();
	inputNeededEmitter.fire();
	strictEqual(capturedSteeringRequests.length, 1, 'Expected duplicate rapid input-needed events to be suppressed');
	output = 'Confirm (y/N):';
	inputNeededEmitter.fire();
	strictEqual(capturedSteeringRequests.length, 2, 'Expected a changed prompt to trigger a new notification');
	} finally {
	activeExecutions.delete(termId);
	}