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TinyFat Docs

Email

Email is the default interface. No apps to install, works from any device.

Your agent’s address

Section titled “Your agent’s address”

Your agent gets a unique name like swiftpebble@tinyfat.com.

This is a real email address. Send from Gmail, Outlook, Apple Mail, your phone — anywhere.

How it works

Section titled “How it works”
You send email → Platform validates → Agent runs → Agent replies
  1. You email yourname@tinyfat.com
  2. Resend receives it, sends webhook to platform
  3. Platform verifies signature, resolves agent, validates sender
  4. Message queued for async delivery
  5. Sandbox wakes, R2 storage mounted, troublemaker starts
  6. Agent processes your message (one turn)
  7. Agent writes response to outbox
  8. Platform sends the reply via Resend
  9. You get the email

Response time: 10-20 seconds warm, 30-60 seconds on cold start.

Email commands

Section titled “Email commands”

Control your agent with commands in the subject or body:

CommandEffect
/clearStart fresh session (keeps history)
/resumeList recent sessions
/resume abc1Resume specific session
/compactCompress context to save tokens
/modelShow current model
/model haikuSwitch to Haiku (fastest)
/model sonnetSwitch to Sonnet (balanced)
/model opusSwitch to Opus (most capable)

Attachments

Section titled “Attachments”

Send files to your agent:

  • Images: PNG, JPG, GIF, WebP — agent can analyze
  • Documents: PDF, TXT, MD — agent can read
  • Data: JSON, CSV — agent can process

Files are available during the turn at /inbox/attachments/.

Sending email from your agent

Section titled “Sending email from your agent”

Your agent writes emails to /data/outbox/email/:

{
  "to": ["recipient@example.com"],
  "subject": "Report ready",
  "body": "Here's the analysis...",
  "status": "pending"
}

The platform picks these up and sends them.

Threading

Section titled “Threading”

Responses thread correctly in email clients:

  • In-Reply-To links to your message
  • References maintains the full chain
  • Gmail, Outlook, Apple Mail all group properly

Security

Section titled “Security”

Allowed senders

Section titled “Allowed senders”

Only whitelisted addresses can trigger your agent:

  • Exact: alice@example.com
  • Domain: @company.com (anyone at domain)

Your signup email is added automatically. Management UI coming soon.

Webhook verification

Section titled “Webhook verification”

Inbound emails are verified using Resend’s webhook signatures (Svix). Invalid payloads are rejected.

Troubleshooting

Section titled “Troubleshooting”

No response

Section titled “No response”
  1. Make sure you’re sending from your signup email
  2. Check your spam folder
  3. Try again — cold starts can occasionally fail

Went to spam

Section titled “Went to spam”

Add your agent’s address to contacts or mark “not spam”.

Threading broken

Section titled “Threading broken”

Some corporate email systems modify headers. Try a personal email client.

Next steps

Section titled “Next steps”