Writing an Email Rule in Plain English

Most rule builders ask you to think like the system. This one asks you to describe the outcome and does the translating.

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Rules decide what Inbox does for you — which messages get a drafted reply, which CRM events produce work, what context the AI pulls in. The editor has two fields, and one of them is optional:

1. Rule name — optional. Leave it blank and one is generated.
2. Describe the rule in natural language — plain English. “When a new email arrives that needs a reply, draft a reply for me to review before it is sent.”

Then Save. That single click both turns the description into a structured rule and stores it; there is no separate generate step. It runs a model and takes a few seconds, and an inline notice asks you not to refresh while it works.

The design decision worth noticing

If the model is unavailable, Save fails and nothing is written.

That is deliberate, and the reasoning is worth carrying into your own systems: saving anyway would have replaced the rule’s filter with one that matches every email. A rule that silently widens to everything is far worse than a save that failed — the first is an automation quietly acting on mail you never intended, the second is an error message and a retry.

Fail closed on the path where partial success is indistinguishable from success. Here that means: no rule is better than a rule whose scope you did not choose.

Editing behaves the same way, with one exception

Change the description and click Save again; it re-structures the rule. Changing only the name just renames it and leaves behaviour alone — which is what you want, because renaming a rule for clarity should never be a behavioural change.

The shape every rule has

A new, empty rule shows a hint block that disappears as soon as you type. Its top strip is the useful part — the shape of every rule is Trigger → Integrations → Output:

Trigger is what makes the rule fire: a new email (Gmail or Outlook), a CRM stage change (Salesforce, HubSpot, Microsoft Dynamics 365), or a Suger marketplace event — a co-sell referral, an entitlement, an offer, or a billing event.

That list is worth reading closely, because it is wider than “email rules” suggests. A rule can fire on a marketplace event and produce email work, which is a different and more useful thing than a mail filter.

Two habits

Describe the outcome, not the mechanism. “Draft a reply for me to review before it is sent” is a better description than an attempt to specify conditions in structured language — the structuring is the part being done for you.

Turn a rule off rather than deleting it while you think. Every row in the list carries an enable switch and a delete button, so disabling never requires opening the rule. A disabled rule is a decision you can reverse; a deleted one is a description you have to write again.

Frequently asked questions

How many fields does a rule have?

Two: an optional name, and a plain-English description of what should happen. Save turns the description into a structured rule and stores it in one click.

What happens if the AI model is unavailable when I save?

Save fails and nothing is written. This is deliberate — saving anyway would have replaced the rule’s filter with one matching every email.

Does renaming a rule change what it does?

No. Changing only the name renames it and leaves the behaviour alone. Changing the description and saving re-structures the rule.

What can a rule fire on?

A new email in Gmail or Outlook, a CRM stage change in Salesforce, HubSpot or Microsoft Dynamics 365, or a Suger marketplace event — a co-sell referral, entitlement, offer or billing event.

How do I stop a rule temporarily?

Use the enable switch on its row in the list. Turning a rule off never requires opening it, and it is reversible in a way deleting is not.

Takeaways

• Two fields, one optional. Describe the outcome; Save structures and stores in one click.
• Save fails closed when the model is unavailable, rather than writing a rule that matches everything.
• Renaming is safe; re-describing re-structures.
• Triggers include CRM stage changes and marketplace events, not just email.
• Disable rather than delete while you are still deciding.

This post owns the editor’s mechanics. For filter craft, context sources and destinations — what a rule can match on and where its output goes — see setting up email rules without writing code, and the inbox app overview for what happens after a rule fires.