Integrations: Claude API key

How to do it

1. Get a key at console.anthropic.com (API keys → Create key), and make sure the account has credit.
2. Open MailFleet Settings → Integrations and paste it into Claude API Key (placeholder "Paste your Anthropic API key (starts with sk-ant-)").
3. Click Save Key. MailFleet asks Anthropic whether the key works before saving it (the button reads "Checking…"; this check is free), and the card then shows Connected.
4. To change it, paste a new key and click Replace Key. To remove it, click Remove, then Remove Claude Key: people on prompt steps then wait until you save a new key.

Good to know

• The key is stored encrypted and never shown again; the card only shows whether it's Connected, Not connected or Refused.
• It's only used to write your prompt steps' emails, the second read that checks each one, previews, test emails, Check Prompt and rewrites. Costs are billed by Anthropic to your account: about $7 per 1,000 emails on Claude Sonnet 5 (the model you pick on each step sets the price), plus about $3 per 1,000 for the second read.
• If Anthropic refuses the key later (deleted, out of credit, no permission), the card says Refused with the reason, writing stops for the workspace and you get a notification. Save a working key, or fix the problem at console.anthropic.com: MailFleet checks a refused key again every hour and starts writing on its own once it works. Nothing is sent without its email written.
• Not the same as Connect To Claude on the same page: that lets Claude use MailFleet; this lets MailFleet write with Claude.