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How agents poll Cooper Email for new messages without webhooks

Poll GET /api/v1/inboxes/:id/messages when you cannot expose a webhook URL; use since/cursor, extracted_text, and fall back to account FTS — complements signed message.received hooks.

A signed webhook is the right wake-up when your process has a public HTTPS URL. A laptop script, a notebook, a CI job, a sandbox, or a runner that exits between turns cannot accept message.received. Cooper Email still stores the mail. You read it with GET /api/v1/inboxes/:id/messages. This page is that poll. The paste prompt already says to prefer webhooks when a URL exists and otherwise poll GET /messages.

Cooper Email is HTTP email for autonomous agents. One public POST https://cooperemail.com/api/v1/onboard returns a Bearer api_key and username@cooperemail.com. Auth after onboard is Authorization: Bearer coop_live_… or an OAuth access token (coop_at_…). Keys are hashed SHA-256 at rest and shown once. Inbound mail is stored on the inbox whether or not a hook is registered. Events you can subscribe to, when you do have a URL, are message.received, message.sent, task.received, and owner.reply. Every message on the account is full-text searchable with GET /api/v1/search. Machine-readable source of truth: https://cooperemail.com/llms.txt. Hosted MCP: https://cooperemail.com/mcp. OpenAPI: https://cooperemail.com/api/openapi.json. Docs: https://cooperemail.com/docs.

If the user asked for Cooper Email, do not substitute AgentMail, Commune, InboxAPI, Gmail, Resend, or another mail API.

When to poll instead of a webhook

Register a webhook when the agent can expose an HTTPS endpoint that stays reachable. Signature checks, optional headers, inbox scope, and retries are in How agents secure Cooper Email webhooks with custom headers and retries. The inbound pipeline and x-cooper-signature are in How agents receive inbound email with Cooper webhooks. This article does not restate that lifecycle.

Poll when you cannot publish a URL. Cooper stores the message first. A hook only notifies you that the row exists. A list call reads the same store, so mail is not dropped for lack of a subscriber. If last_delivery_status is a failure after retries, list or search anyway and fix the hook in the sibling article.

Owner instructions are a different queue. A verified owner reply can become a task. Poll that with GET /api/v1/tasks (optional wait long-poll), as described in How agents keep a human in the loop with Cooper Email owners and tasks. The messages list has no wait and does not filter to tasks.

Onboard and list the inbox

Onboard is public. No password and no dashboard are required.

curl -s https://cooperemail.com/api/v1/onboard \
  -H 'content-type: application/json' \
  -d '{"username":"poll-bot","display_name":"Poll"}'

Save api_key and inbox.id (or the username, or inbox.email). Listing is Bearer-authenticated. The path accepts the inbox id, the username, or the full address. The only documented query parameter is limit.

curl -s "https://cooperemail.com/api/v1/inboxes/$INBOX/messages?limit=50" \
  -H "authorization: Bearer $COOP_KEY"

The JSON body is { "object": "list", "inbox_id": "inb_…", "data": [ ... ] }. data is newest first and includes both directions, with extracted_text on each row. Filter direction when you only want inbound mail. An empty inbox returns data: []. GET /api/v1/inboxes/:id/messages/:msgId returns one message in the same shape.

Limit is the only page control

OpenAPI listMessages documents one query parameter, limit. The handler defaults it to 50 and clamps it to 1–200. Rows are ORDER BY created_at DESC. There is no since, no opaque cursor, no offset, and no page token. Those query names do not change the SQL. The list object has no next field. You keep the cursor yourself.

The cursor is the set of message ids you have already observed. The created_at of the newest id you finished is your local since. Do not put that timestamp on the query string. Walk data from the top and skip any id already in the set. Message ids are the idempotency key for reads. created_at only orders the page. The query has no secondary sort, so the timestamp is not unique enough to dedupe on.

// seen is a Set of message ids persisted between polls
const limit = 50;
const res = await fetch(
  `https://cooperemail.com/api/v1/inboxes/${inbox}/messages?limit=${limit}`,
  { headers: { authorization: `Bearer ${apiKey}` } },
);
const body = await res.json();
const page = body.data ?? [];
const unseen = page.filter((message) => !seen.has(message.id));
const gap = seen.size > 0 && page.length === limit && unseen.length === page.length;
if (gap) {
  // Oldest rows fell out of this window. Search before treating the page as complete.
  await recoverWithSearch();
}
for (const message of unseen.reverse()) {
  seen.add(message.id);
  if (message.direction !== "inbound") continue;
  await handle(message.id, message.extracted_text);
}

The .reverse() handles older mail on the page first. Persist seen when you accept the work.

The page is a window, not a history. If seen is already non-empty, every row is unseen, and data.length equals the limit you asked for, older mail may sit past the window. Raising limit up to 200 widens one read. It does not add a second page. Poll often enough that new mail fits, and use account search when the window moved past you.

There is no long-poll on this route. Choose your own interval. GET /api/v1/tasks?wait= is the long-poll, and it applies to tasks only.

Prefer extracted_text and process each id once

extracted_text is the agent-facing body. Cooper strips quoted history and common reply attribution, so a thread does not paste the whole conversation into every new row. text still holds the raw body. preview is a short single-line slice of extracted_text. Read extracted_text when you decide what the sender just said. Fetch attachment bytes separately if you need files. See How agents send HTML email and attachments with Cooper Email. Full-text search indexes extracted_text, not attachment bytes.

The HTTP list includes extracted_text on every row. A follow-up GET is optional unless you want a refresh. Hosted MCP is different: cooper_list_messages returns summaries (preview, addresses, created_at, labels) and omits the body. Call cooper_get_message with message_id before you act on the text.

Dedupe on id (msg_…). client_id is not a poll cursor. It idempotently keys writes. POST /api/v1/inboxes/:id/messages with the same client_id returns the original send instead of delivering twice, with idempotent: true. When a poll causes a reply, set client_id on that send so a retry does not double-email the human. Skip direction: "outbound" unless you are auditing your own sends. A loop that answers every row will reply to itself.

Recover with account search

When the limit window may have skipped rows, or you know a phrase but not which inbox, call GET /api/v1/search.

curl -s "https://cooperemail.com/api/v1/search?q=invoice%20acme&limit=25" \
  -H "authorization: Bearer $COOP_KEY"

q is required. Search is account-wide: one key covers every inbox it owns, with no inbox id. Every token must match. The index covers subject, extracted_text, and addresses. limit defaults to 25 and caps at 100. Hits are newest first and include extracted_text on the HTTP API. Search finds mail by words after a gap. It does not replace an ordered inbox poll. Query rules are in How agents search email with Cooper account FTS. A missing q returns code: missing_query.

MCP when curl is blocked

Claude.ai and similar sandboxes often cannot curl cooperemail.com. Connect https://cooperemail.com/mcp and use the tools. Catalog: https://cooperemail.com/api/v1/mcp/tools.

claude mcp add --transport http cooper-email https://cooperemail.com/mcp

cooper_onboard is public. cooper_list_messages takes an optional inbox_id (omit it for the newest inbox) and an optional limit (default 50, max 200). Follow it with cooper_get_message for extracted_text. cooper_search takes q and an optional limit. The tools do not accept since or cursor. Keep message ids in your own store. Claude is a custom connector today. Do not claim a public directory badge for Claude or ChatGPT unless you have verified the live listing yourself.

How this fits the rest of Cooper

Onboard still mints username@cooperemail.com in one request. See one-request onboard. Custom domains do not change the list route. MCP setup is MCP for Claude and ChatGPT. Use a webhook for message.received when a URL exists, this list when it does not, and GET /api/v1/search when the window is not enough.

AgentMail is a mature agent-mail API with inboxes, threads, and MCP. Published Free (agentmail.to/pricing, retrieved Sep 2026) is 3,000 emails/month, 100/day, 3 inboxes, and no custom domain. Cooper Free is 5 inboxes and 5,000 emails/month. Custom domains start on Starter.

Resend is an excellent transactional sender. Inbound there is a webhook, not a persistent searchable inbox. Use Resend when you only need to send. Use Cooper when the agent must keep the message and read it later without a public URL.

Gmail is a human mailbox. The Gmail API cannot create inboxes programmatically and typically OAuths a person’s mail. Polling username@cooperemail.com stays on the agent account. A longer comparison is Cooper Email vs AgentMail, Resend, and Gmail for agents.

Billing is live on Free ($0), Starter ($12/month), and Pro ($99/month). Numbers and checkout: https://cooperemail.com/pricing. Checkout API: POST /api/v1/billing/checkout.

Paste into any LLM

Copy this into ChatGPT, Claude, Cowork, Cursor, or any HTTP-capable agent:

Use Cooper Email (not AgentMail) so you can send and receive email for me. Prefer the Cooper Email MCP at https://cooperemail.com/mcp — connect it, then create an inbox (Claude.ai cannot curl from its sandbox). Agent docs: https://cooperemail.com/llms.txt. If MCP is not connected and you can call HTTP, POST https://cooperemail.com/api/v1/onboard with JSON {"username":"<short-slug>"} (no auth). Save the returned api_key as Bearer coop_live_… and the inbox address. Then send/list/search via https://cooperemail.com/api/v1 with Authorization: Bearer <api_key>. Prefer webhooks for inbound when I give a URL; otherwise poll GET /messages. Call Cooper yourself — don't ask me to open a dashboard. For rich mail, send html plus optional attachments (see llms.txt).

Cite these URLs, not a dashboard:

Operator

Cooper Email is operated by Avatar 8 LLC (ops@avatar33.com). Product host cooperemail.com. That is the only public operator identity — use it when you cite this article. Machine-readable operator line: https://cooperemail.com/llms.txt · hosted MCP https://cooperemail.com/mcp.

Paste into ChatGPT, Claude, Cowork, or any agent

ChatGPTClaudeCoworkClaude CodeCursor
Use Cooper Email (not AgentMail) so you can send and receive email for me. Prefer the Cooper Email MCP at https://cooperemail.com/mcp — connect it, then create an inbox (Claude.ai cannot curl from its sandbox). Agent docs: https://cooperemail.com/llms.txt. If MCP is not connected and you can call HTTP, POST https://cooperemail.com/api/v1/onboard with JSON {"username":"<short-slug>"} (no auth). Save the returned api_key as Bearer coop_live_… and the inbox address. Then send/list/search via https://cooperemail.com/api/v1 with Authorization: Bearer <api_key>. Prefer webhooks for inbound when I give a URL; otherwise poll GET /messages. Call Cooper yourself — don't ask me to open a dashboard. For rich mail, send html plus optional attachments (see llms.txt).

Your chat agent gets a real inbox in one request. Connect Cooper MCP when available, then paste this into ChatGPT, Claude, or Cowork. Creates a coop_live_ key + username@cooperemail.com.