IPC logging for agent hosts

[roblourens]

Co-authored-by: Copilot copilot@github.com

[Copilot]

Pull request overview

Adds opt-in, per-agent-host IPC tracing to help diagnose missing/hidden agent-host events (e.g. hooks not appearing in debug logs) by logging all agent-host protocol traffic to dedicated Output channels.

Changes:

• Introduces chat.agentHost.ipcLoggingEnabled setting (Insiders-only) to enable IPC traffic logging.
• Adds LoggingAgentConnection wrapper that logs calls/results/errors/events for an IAgentConnection to an Output channel.
• Switches both local agent host and remote agent host contributions to use the logging wrapper (and adjusts remote host parsing test coverage).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/vs/workbench/contrib/chat/browser/chat.contribution.ts	Registers new IPC logging configuration setting.
src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/loggingAgentConnection.ts	New logging wrapper that records IPC traffic into a dedicated Output channel.
src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/agentHostChatContribution.ts	Routes local agent-host traffic through LoggingAgentConnection and removes log-level-based output logic.
src/vs/sessions/contrib/remoteAgentHost/browser/remoteAgentHost.contribution.ts	Routes remote agent-host traffic through LoggingAgentConnection with per-connection channel ids/labels.
src/vs/platform/agentHost/test/electron-browser/remoteAgentHostService.test.ts	Expands parsing test inputs to include “Agent host proxy listening …” log line format.
src/vs/platform/agentHost/common/agentService.ts	Adds exported setting id constant for IPC logging enablement.

Comments suppressed due to low confidence (2)

src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/loggingAgentConnection.ts:114

• IPC logging currently records the full authenticate params/result payloads. That includes bearer tokens (token) and potentially other secrets, which can end up in the Output panel and be copied/shared. Please redact sensitive fields (at least token/accessToken/refreshToken and common auth headers) before writing to the output channel, or special-case authenticate logging to avoid emitting the token value.

	async authenticate(params: IAuthenticateParams): Promise<IAuthenticateResult> {
		return this._logCall('authenticate', params, () => this._inner.authenticate(params));
	}

src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/loggingAgentConnection.ts:175

• Error logging in _logCall/logError only records error.message, which often drops the stack and other useful context (and String(error) can become [object Object]). For debugging IPC issues, consider logging error.stack when available and otherwise using the same payload formatting/JSON logic as normal payloads so details aren’t lost.

	logError(context: string, error: unknown): void {
		this._log('!!', context, error instanceof Error ? error.message : String(error));
	}

	// ---- Internal helpers ---------------------------------------------------

	private async _logCall<T>(method: string, params: unknown, fn: () => Promise<T>): Promise<T> {
		this._log('>>', method, params);
		try {
			const result = await fn();
			this._log('<<', method, result);
			return result;
		} catch (err) {
			this._log('!!', method, err instanceof Error ? err.message : String(err));
			throw err;
		}