Email Deliverability Agent with Claude Code

Nobody reads this agent's output most days, which is rather the point: it marks a bounced contact and moves on. Getting it wrong surfaces weeks later in a rep's pipeline, so the run has to check the Mailgun history, find exactly one HubSpot contact, and change only the fields your rules name. Claude Code's habit of reading everything before acting fits a job where the write is small and the check is not.
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Free to start · guided setup · switch agents any time.

Live demo

Watch it work before it's live

Run a staged conversation — no account needed. The agent handles it for real while a simulated world answers its tool calls; nothing touches real accounts, and nothing is actually sent.

Maartje de Vries

mg.zorgflow.nl invoice remindersm.devries@thuiszorg-lindehof.nl

550 5.1.1 The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos. First permanent failure for this address, sent by the July invoice reminder campaign. The contact opened eleven emails before this and last clicked on 14 June.

What you'll need

Set up in minutes

Using this template drops you into a guided setup. It asks exactly this, nothing else:

  1. Connect Mailgun

    One sign-in. The agent acts through your account, scoped to what this template uses.

  2. Connect HubSpot

    One sign-in. The agent acts through your account, scoped to what this template uses.

  3. Connect Slack

    One sign-in. The agent acts through your account, scoped to what this template uses.

  4. List hygiene rules

    What a hard bounced address should become in HubSpot: which field to set, to which value, and where the bounce details get written. The agent only ever makes the changes this names.

  5. Alert criteria

    Which bounces are worth interrupting someone for, for example a paying customer domain, a VIP account, or more than five bounces on one domain in a day. Everything else stays silent.

  6. Runs on Claude Code

    Preselected for this page — connect your Claude Code account during setup, or switch to NoClick's built-in models with one click.

  7. Watch it handle a test run

    A staged conversation against a simulated world — then it’s live.

A considered pairing

Why Claude Code for this agent

Checks before it writes

Bounce record, event history, then a contact search, and only then a field update. The order is the safety property here.

Handles the ambiguous match

Zero contacts or two contacts means change nothing and report it. Applying an exception rule consistently is what keeps a CRM clean.

Good to know

Before you fork

How many runs will this be?

One per hard bounce, so it tracks list health rather than send volume, and a healthy list is a few hundred runs on a send day. Each run is short: two Mailgun reads, one HubSpot search and usually a single field update. A freshly purchased list will fire far more, which is itself information worth having.

Other editions

Run it with a different agent

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Make it yours

Put Email Deliverability Agent to work on Claude Code.

Free to start. Guided setup, a staged test run, and a workflow you can change at every step.