Track Email Opens From Your Agent's Outreach

You built an outreach agent, it sent 80 follow-ups this week, and you have no idea what happened to any of them. Did the prospect open the message? Click the demo link? Is the silence a "no" or a spam-folder problem? Without engagement signals, your agent is firing into the void and your follow-up logic is guesswork.

The fix has two parts: turn tracking on when you send, and subscribe to the webhooks that report what recipients do.

Tracking starts at send time, not after

Opens, clicks, and replies are only reported for messages sent with tracking enabled — you can't retroactively track a message that's already out. On the — the beta feature that gives an agent its own dedicated mailbox rather than a connected Gmail or Outlook grant — know that native message tracking isn't available on its direct API sends. message.opened and message.link_clicked aren't emitted for messages sent through POST /messages/send on those accounts. Deliverability visibility comes instead from the send-side triggers: message.send_success, message.send_failed, and message.bounce_detected.

In practice that's a reasonable trade. Send-side triggers tell you what actually got delivered or bounced, replies still land in the agent's inbox and fire message.created, and reply-based routing — the strongest signal anyway — works exactly the same. The tracking flags above apply when you're sending through connected provider grants, which is how a lot of outreach tooling runs.

Two smaller gotchas

Each trigger also ships a .legacy variant — message.opened.legacy, message.link_clicked.legacy, thread.replied.legacy — for applications on the older notification format. New integrations should subscribe to the non-legacy names; mixing the two gets you duplicate events with different payload shapes, which is a miserable thing to debug.

And remember what tracking actually does: it rewrites your message content and pixels your recipients. The flags work the same whether the sending grant is Google, Microsoft, or another provider, so one send path covers your whole sender base — but that also means your disclosure obligations follow every message. Honor consent, disclose tracking where your jurisdiction requires it, and don't track links that carry sensitive data.

Wire the weakest signal last

Build the reply path first, clicks second, opens last — the reverse of how most teams do it, and the order that matches signal quality. Full payload schemas and per-provider behavior are in the tracking recipe.

Next step: add tracking_options to one live campaign, log the three trigger types for a week, and compare your open rate against your click rate. If they tell wildly different stories — which signal is your follow-up logic currently trusting?