Harden rinbox agent mailbox pipeline: loop detection, rate limits, envelope fix

- Fix executeApproval SMTP envelope to authenticate as SMTP_USER (Mailcow sender mismatch)
- Add reply loop detection: skip auto-replies, noreply, mailer-daemon, postmaster senders
- Per-sender rate limit: 3 replies/hr per sender per agent mailbox
- Daily send cap: 50 replies/day per agent mailbox
- Reply length cap: truncate agent replies at 2000 chars
- Bootstrap existing spaces on init: provision missing team inbox + agent mailbox docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/rinbox/mod.ts

@@ -1727,8 +1727,7 @@ async function syncAgentMailbox(creds: AgentImapCreds) {
 				try {
 					const parsed = await simpleParser(msg.source);
 
-					const threadId = generateId();
+					const fromAddr = (parsed.from?.value?.[0]?.address || '').toLowerCase();
-					const fromAddr = parsed.from?.value?.[0]?.address || '';
 					const fromName = parsed.from?.value?.[0]?.name || '';
 					const subject = parsed.subject || '(no subject)';
 					const messageId = parsed.messageId || null;
@@ -1737,6 +1736,56 @@ async function syncAgentMailbox(creds: AgentImapCreds) {
 					const toAddrs = parsed.to?.value?.map((a: any) => a.address).filter(Boolean) || [];
 					const ccAddrs = parsed.cc?.value?.map((a: any) => a.address).filter(Boolean) || [];
 
+					// ── Reply loop detection ──
+					const isAutoReply =
+						fromAddr.endsWith('-agent@rspace.online') ||
+						fromAddr.startsWith('noreply@') ||
+						fromAddr.startsWith('no-reply@') ||
+						fromAddr.startsWith('mailer-daemon@') ||
+						fromAddr.startsWith('postmaster@') ||
+						/^(auto[_-]?reply|out[_-]?of[_-]?office)/i.test(subject) ||
+						parsed.headers?.get('auto-submitted')?.toString() !== undefined &&
+						parsed.headers?.get('auto-submitted')?.toString() !== 'no' ||
+						parsed.headers?.get('x-auto-response-suppress') !== undefined;
+
+					if (isAutoReply) {
+						// Store as skipped thread but don't trigger MI processing
+						const skipThreadId = generateId();
+						_syncServer!.changeDoc<MailboxDoc>(agentDoc.docId, `Agent IMAP (skipped auto-reply): ${subject}`, (d) => {
+							d.threads[skipThreadId] = {
+								id: skipThreadId,
+								mailboxId: d.mailbox.id,
+								messageId,
+								subject,
+								fromAddress: fromAddr,
+								fromName,
+								toAddresses: toAddrs,
+								ccAddresses: ccAddrs,
+								bodyText: parsed.text || '',
+								bodyHtml: parsed.html || '',
+								tags: ['agent-inbound-skipped'],
+								status: 'closed',
+								isRead: true,
+								isStarred: false,
+								assignedTo: null,
+								hasAttachments: parsed.attachments?.length > 0 || false,
+								receivedAt: parsed.date?.getTime() || Date.now(),
+								createdAt: Date.now(),
+								comments: [],
+								inReplyTo: inReplyTo || null,
+								references,
+								direction: 'inbound',
+								parentThreadId: null,
+							};
+						});
+						console.log(`[Inbox] Agent ${creds.email} skipped auto-reply from ${fromAddr}: "${subject}"`);
+						if (msg.uid > maxUid) maxUid = msg.uid;
+						count++;
+						continue;
+					}
+
+					const threadId = generateId();
+
 					_syncServer!.changeDoc<MailboxDoc>(agentDoc.docId, `Agent IMAP: ${subject}`, (d) => {
 						d.threads[threadId] = {
 							id: threadId,
@@ -1802,6 +1851,16 @@ async function syncAllAgentMailboxes() {
 	}
 }
 
+// ── Agent reply rate limiting ──
+const _agentReplyTracker = new Map<string, { count: number; windowStart: number }>();
+const AGENT_RATE_LIMIT = 3;        // max replies per sender per window
+const AGENT_RATE_WINDOW = 3600000; // 1 hour
+
+const _agentDailySends = new Map<string, { count: number; day: string }>();
+const AGENT_DAILY_CAP = 50;        // max replies per agent mailbox per day
+
+const AGENT_REPLY_MAX_LENGTH = 2000; // max characters in agent reply
+
 /**
  * Process an inbound agent email through MI agentic loop.
  * Creates an auto-approved reply and sends it via SMTP.
@@ -1817,6 +1876,44 @@ async function processAgentMI(docId: string, threadId: string, spaceSlug: string
 	const agent = Object.values(doc.agentInboxes)[0];
 	if (!agent?.autoReply) return;
 
+	// ── Per-sender rate limit ──
+	const senderKey = `${spaceSlug}:${thread.fromAddress!.toLowerCase()}`;
+	const now = Date.now();
+	const tracker = _agentReplyTracker.get(senderKey);
+	if (tracker) {
+		if (now - tracker.windowStart < AGENT_RATE_WINDOW) {
+			if (tracker.count >= AGENT_RATE_LIMIT) {
+				console.warn(`[Inbox] Rate limit: ${thread.fromAddress} exceeded ${AGENT_RATE_LIMIT} replies/hr for ${spaceSlug}`);
+				return;
+			}
+			tracker.count++;
+		} else {
+			tracker.count = 1;
+			tracker.windowStart = now;
+		}
+	} else {
+		_agentReplyTracker.set(senderKey, { count: 1, windowStart: now });
+	}
+
+	// ── Daily send cap per agent mailbox ──
+	const today = new Date().toISOString().slice(0, 10);
+	const dailyKey = spaceSlug;
+	const daily = _agentDailySends.get(dailyKey);
+	if (daily) {
+		if (daily.day === today) {
+			if (daily.count >= AGENT_DAILY_CAP) {
+				console.warn(`[Inbox] Daily cap: ${spaceSlug}-agent hit ${AGENT_DAILY_CAP} replies for ${today}`);
+				return;
+			}
+			daily.count++;
+		} else {
+			daily.count = 1;
+			daily.day = today;
+		}
+	} else {
+		_agentDailySends.set(dailyKey, { count: 1, day: today });
+	}
+
 	try {
 		const { miRegistry } = await import('../../server/mi-provider');
 		const { runAgenticLoop } = await import('../../server/mi-agent');
@@ -1860,6 +1957,11 @@ async function processAgentMI(docId: string, threadId: string, spaceSlug: string
 
 		if (!replyText.trim()) return;
 
+		// ── Reply length cap ──
+		if (replyText.length > AGENT_REPLY_MAX_LENGTH) {
+			replyText = replyText.slice(0, AGENT_REPLY_MAX_LENGTH) + '...[truncated]';
+		}
+
 		// Create auto-approved approval and execute it
 		const approvalId = generateId();
 		const replySubject = thread.subject.startsWith('Re:') ? thread.subject : `Re: ${thread.subject}`;
@@ -2173,6 +2275,69 @@ function seedTemplateInbox(space: string) {
 	console.log(`[Inbox] Template seeded for "${space}": 1 mailbox (${space}-inbox), 3 threads`);
 }
 
+/**
+ * Bootstrap mailboxes for spaces created before rinbox existed.
+ * Iterates all space docs and ensures each has team inbox + agent mailbox.
+ */
+async function bootstrapExistingSpaces() {
+	if (!_syncServer) return;
+
+	try {
+		// Collect all known space slugs from existing inbox docs
+		const existingSlugs = new Set<string>();
+		const existingAgentSlugs = new Set<string>();
+		for (const id of _syncServer.listDocs()) {
+			const parts = id.split(':');
+			if (parts.length >= 4 && parts[1] === 'inbox' && parts[2] === 'mailboxes') {
+				const doc = _syncServer.getDoc<MailboxDoc>(id);
+				if (doc) {
+					if (doc.mailbox.slug.endsWith('-agent')) {
+						existingAgentSlugs.add(parts[0]);
+					} else {
+						existingSlugs.add(parts[0]);
+					}
+				}
+			}
+		}
+
+		// Find all space slugs from ANY doc on the SyncServer (spaces module stores space docs)
+		const allSpaceSlugs = new Set<string>();
+		for (const id of _syncServer.listDocs()) {
+			const parts = id.split(':');
+			// Space docs follow pattern: {space}:spaces:... or just use the first segment
+			if (parts.length >= 2 && parts[0] !== 'global') {
+				allSpaceSlugs.add(parts[0]);
+			}
+		}
+
+		let bootstrapped = 0;
+		for (const slug of allSpaceSlugs) {
+			if (slug === 'demo' || slug === 'template') continue; // skip demo/template
+
+			if (!existingSlugs.has(slug)) {
+				initSpaceInbox(slug, 'did:bootstrap');
+				// Provision Mailcow alias
+				fetch(`${ENCRYPTID_INTERNAL}/api/internal/spaces/${slug}/alias`, { method: 'POST' }).catch(() => {});
+				bootstrapped++;
+			}
+			if (!existingAgentSlugs.has(slug)) {
+				initAgentMailbox(slug, 'did:bootstrap');
+				// Provision Mailcow agent mailbox
+				fetch(`${ENCRYPTID_INTERNAL}/api/internal/spaces/${slug}/agent-mailbox`, { method: 'POST' }).catch(() => {});
+				bootstrapped++;
+			}
+		}
+
+		if (bootstrapped > 0) {
+			console.log(`[Inbox] Bootstrap: provisioned ${bootstrapped} missing mailboxes across ${allSpaceSlugs.size} spaces`);
+		} else {
+			console.log(`[Inbox] Bootstrap: all ${allSpaceSlugs.size} spaces already have mailboxes`);
+		}
+	} catch (e: any) {
+		console.error(`[Inbox] Bootstrap error:`, e.message);
+	}
+}
+
 export const inboxModule: RSpaceModule = {
 	id: "rinbox",
 	name: "rInbox",
@@ -2188,6 +2353,8 @@ export const inboxModule: RSpaceModule = {
 		console.log("[Inbox] Module initialized (Automerge-only, no PG)");
 		// Pre-warm SMTP transport
 		if (SMTP_USER) getSmtpTransport().catch(() => {});
+		// Bootstrap mailboxes for spaces created before rinbox existed
+		setTimeout(() => bootstrapExistingSpaces(), 10000);
 	},
 	async onSpaceCreate(ctx) {
 		initSpaceInbox(ctx.spaceSlug, ctx.ownerDID || 'did:unknown');