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AI Playbook

Automation: Inbox Triage

📖 2 min read resourcesautomations
Auto-classify incoming email by priority, summarize it in one line, and apply a label — so you read only what matters.

Every new email gets classified (Urgent / Action / FYI / Newsletter / Spam), summarized in one line, and labeled automatically. You open your inbox already sorted.

How it works

flowchart LR
    A[New email<br/>Gmail trigger] --> B[Send subject + body<br/>to the LLM]
    B --> C[LLM returns JSON<br/>category + summary + label]
    C --> D[Apply Gmail label<br/>+ optional Slack ping if Urgent]

You’ll need

  • Gmail (or any IMAP inbox)
  • An LLM API key — Haiku 4.5 / Flash / DeepSeek Flash are ideal (cheap, fast, run on every email)
  • n8n or Zapier

Build it in n8n

  1. Gmail Trigger node → “On message received” (or poll every N minutes).
  2. HTTP Request node → the reusable AI transform node. Set its input to: Subject: {{ $json.subject }}\n\nBody: {{ $json.snippet }} and paste the system prompt below.
  3. Code node → return JSON.parse($json.content[0].text) to get {category, summary, label} as fields.
  4. Gmail node → “Add label” using {{ $json.label }} (create the labels once in Gmail first).
  5. (Optional) IF node → if category == "Urgent", a Slack node posts the summary to your DMs.

The AI prompt

System prompt (paste into the HTTP node’s system):

You triage email. Given a subject and body, classify it and summarize it.


Categories:
- Urgent: needs a reply or action within 24h (deadlines, outages, the boss)
- Action: needs me to do something, but not urgent
- FYI: informational, no action needed
- Newsletter: marketing, digests, automated updates
- Spam: junk or phishing


Respond with ONLY valid JSON, no prose:
{"category": "...", "summary": "<one sentence, <=15 words>", "label": "<category>"}

Zapier alternative

Trigger Gmail → New Email → action OpenAI/Anthropic → Send Prompt (paste the same system prompt + the email as the message) → Formatter → Utilities (parse JSON) → Gmail → Add Label. Add a Filter before a Slack step to ping only on Urgent.

Cost

~250 input + ~40 output tokens per email. On Haiku 4.5 (1/1/5 per 1M) that’s roughly $0.0005/email — about 15¢ for 300 emails. On DeepSeek V4 Flash it’s ~10× cheaper.

Variations

  • Auto-draft replies for the “Action” bucket (draft only — never auto-send; let a human approve).
  • Add a sender allow-list so known contacts skip triage.
  • Route by project: extend the categories to your actual labels (e.g. “Invoices”, “Recruiting”).