Guides · Tag
reliability
30 guides tagged reliability.
Inboxes · Sep 30, 2026
Thread ID vs Message-ID in an Agent Inbox
Agent email thread ID vs message ID vs the Message-ID header: which to store, which a counterparty can forge, and what reply_to_message_id accepts.
Integrations · Sep 29, 2026
n8n AI Agent Gmail Node: Invalid Email Address
Why the n8n AI agent Gmail node throws an invalid email address error: it only checks for an @. The model outputs that trip it, and the ones that slip past.
Developers · Sep 29, 2026
What message.submission_unknown Actually Means
The send was attempted and nobody knows if it went out. What message.submission_unknown means, the silent path to it, and why resending is the wrong move.
Comparisons · Sep 29, 2026
Gmail Blocked My Bot From Sending Email: 4 Causes
Gmail blocked my bot from sending email: four different Google enforcement paths, the exact error strings for each, and which ones configuration can fix.
Comparisons · Sep 29, 2026
Gmail MCP Refresh Tokens Expiring Every 7 Days
Why a Gmail MCP refresh token expires every 7 days, what Google requires to stop it, and the other causes that break the same connection on a different clock.
Inboxes · Sep 29, 2026
Why Your Agent's Email Lands in Spam
Why does my AI agent email go to spam? The three agent-specific causes, what the platform reports back, and the part no sender can see.
Developers · Sep 28, 2026
Agent Email Bounced 550 5.7.1: What It Means
Agent email bounced 550 5.7.1? Which variant you hit, why it is rarely your DNS on a shared domain, and why the agent must stop, not reword and resend.
Developers · Sep 28, 2026
Retry, Backoff and Error Handling for Agent Email
Agent email error handling that sorts every error by whether a retry can help: a decision table, what backs off, and what goes to a human.
Developers · Sep 28, 2026
Validating an Address Before Your Agent Sends
How to validate an email address before your agent sends: the syntax and DNS checks that are safe to run, and why probing the mailbox is not.
Controls · Sep 27, 2026
Monitor Every Email Your Agent Sends
How to monitor what emails my agent sent: four alerts built only from events that actually fire, and why two obvious ones would stay green forever.
Controls · Sep 27, 2026
Stopping an Infinite Agent Auto-Reply Loop
Four stopping rules that end an agent email loop with an auto responder: a thread reply budget, auto-reply signals, a sender window, and an approval gate.
Email for Agents · Sep 27, 2026
Two AI Agents Emailing Each Other: A Design Guide
Two AI agents emailing each other rarely stop on their own: why courtesy keeps the thread alive, how threading works, when to hand off, how to test it.
Inboxes · Sep 26, 2026
Timeouts for an Agent Waiting on an Email Reply
A timeout pattern for an agent waiting on an email reply: three states, the events that move them, in-thread nudges, and defaults by context.
Developers · Sep 26, 2026
Resume an Agent Workflow When a Reply Arrives
How to resume an agent workflow when an email reply arrives: key on thread_id, dedupe message.received by event ID, and catch replies that break the thread.
Developers · Sep 23, 2026
Agent Email Polling vs Webhooks: A Decision Table
Agent email polling vs webhooks, decided on failure modes: cursor semantics, event-id dedup, and the exact 4xx codes that kill a delivery on the first try.
Integrations · Sep 23, 2026
A LangChain Email Tool That Can Receive
A langchain email tool that receives as well as sends: the current ToolRuntime interface, idempotency keys that survive a resume, and which events fire.
Developers · Sep 23, 2026
Your Agent Sent the Same Email Twice. Why
Four reasons an agent sent the same email twice, each with a different fix: a keyless retry, a replayed event, two turns, and a second approval.
Inboxes · Sep 23, 2026
What Happens When an Agent's Email Allowance Runs Out
Sending returns HTTP 402, not 429. What keeps working, how a unit is counted, which reservations stay held, and the upstream quota you do not control.
Developers · Sep 22, 2026
My Agent Says It Sent It. Nobody Received It
Your AI agent says it sent an email and nobody received it. Work the states in order, learn which ones emit no event at all, and never retry one.
Integrations · Sep 22, 2026
Make.com Scenarios With an Agent-Owned Inbox
Make a Make.com AI agent send email from its own address: the HTTP call, an Idempotency-Key that survives Make's retry, and inbound events.
Integrations · Sep 22, 2026
Pydantic AI Email Tool: Typed Send Results
Give a Pydantic AI email tool a discriminated union return type, so a model can never read accepted as delivered or a queued draft as a sent message.
Integrations · Sep 22, 2026
Give a Zapier Agent Its Own Email Address
Zapier's email actions send as the account you connected. Give a Zapier agent an email address of its own: the send call, the key, and inbound.
Developers · Sep 21, 2026
Accepted vs Delivered: What an Email Status Proves
Queued, accepted, delivered, bounced, unknown: what each email status actually proves, what it does not, and the correct next action for every one of them.
Developers · Sep 21, 2026
Agent Email API: Send, Receive and Reply in One Loop
Build the full two-way loop over REST: scoped keys, idempotent sends, the states a message moves through, inbound events, and replies that thread correctly.
Integrations · Sep 21, 2026
n8n AI Agent Email Inbox Without the Gmail Node
Wire an n8n AI agent email inbox to the HTTP Request node: the send call, an Idempotency-Key that survives every n8n retry, and signed inbound webhooks.
Developers · Sep 21, 2026
Keep an Agent's Replies in the Right Email Thread
How Message-ID, In-Reply-To and References decide threading, why subject matching breaks, and how to keep an agent reply in the right conversation.
Developers · Sep 21, 2026
Handle Email Webhooks Without Processing Events Twice
Verify the signature against the raw body, deduplicate by event ID, enqueue durably, and keep a webhook retry from re-sending the email that produced it.
Developers · Sep 21, 2026
Test an Agent's Email Without Sending Real Mail
Use non-routable test inboxes to simulate inbound mail, exercise drafts, approvals and webhooks, and verify agent behavior before a live message goes out.
Developers · Sep 21, 2026
Test an Agent's Inbound Email Loop in CI
A routable test mailbox needs a message actually transmitted. Inject one instead: a CI job asserting received, parsed, threaded and replied.
Developers · Sep 20, 2026
Idempotency Keys: Stop an Agent Sending Duplicate Emails
How send idempotency works: canonical payload hashing, the 30-day replay window, conflict versus expiry, and why retrying an unknown outcome is unsafe.