Imported from tiangong-ai/agent-skills (email-smtp-send/SKILL.md) via skills.sh. Install upstream with npx skills add tiangong-ai/agent-skills --skill email-smtp-send. Copyright stays with the author.

Email SMTP Send

Core Goal

• Send outbound email via SMTP with env-configured credentials.
• Attach local files into MIME email payload when requested.
• Optionally append the sent message to IMAP sent mailbox for cross-client visibility.
• Validate SMTP and sent-sync configuration before delivery.
• Return machine-readable JSON status/error output.

Workflow

1. Configure SMTP env vars (see references/env.md and assets/config.example.env).
2. Optional: configure IMAP sent-sync env vars and install imapclient when sync is enabled.
3. Validate configuration:

python3 scripts/smtp_send.py check-config

4. Send one email:

python3 scripts/smtp_send.py send \
  --to recipient@example.com \
  --subject "SMTP test" \
  --body "Hello from email-smtp-send"

5. Send with attachments:

python3 scripts/smtp_send.py send \
  --to recipient@example.com \
  --subject "Package delivery" \
  --body "See attachments." \
  --attach ./report.pdf \
  --attach ./appendix.xlsx

6. Send and sync to sent mailbox:

python3 scripts/smtp_send.py send \
  --to recipient@example.com \
  --subject "Synced send" \
  --body "This message will be appended to Sent Items." \
  --sync-sent \
  --sent-mailbox "Sent Items"

Output Contract

• check-config prints sanitized SMTP config + defaults + sent-sync config JSON.
• send success prints one type=status JSON object containing:
  • event=smtp_sent
  • sender, recipient summary, subject, SMTP host/port
  • message_id
  • attachment_count and attachments[] metadata
  • sent_sync object with enabled, required, appended, and sync metadata/error
• send failures print type=error JSON to stderr with one of:
  • event=smtp_send_invalid_args
  • event=smtp_send_failed
  • event=smtp_sent_sync_failed (only when sync is required and sync fails)

Parameters

• send --to: required recipient, repeatable or comma-separated.
• send --cc: optional CC recipients.
• send --bcc: optional BCC recipients.
• send --subject: optional subject (defaults from env).
• send --body: optional body (defaults from env).
• send --content-type: plain or html.
• send --from: optional sender override.
• send --attach: optional local attachment path, repeatable or comma-separated.
• send --max-attachment-bytes: max bytes allowed per attachment.
• send --message-id: optional Message-ID header.
• send --in-reply-to: optional In-Reply-To header.
• send --references: optional References header.
• send --sync-sent|--no-sync-sent: force-enable/disable IMAP sent sync for this send.
• send --sent-mailbox: override sent mailbox.
• send --sent-flags: IMAP APPEND flags, comma-separated (default \Seen).
• send --sent-sync-required: return non-zero if SMTP succeeds but sent sync fails.

Environment defaults:

• SMTP_HOST, SMTP_PORT, SMTP_SSL, SMTP_STARTTLS
• SMTP_USERNAME, SMTP_PASSWORD, SMTP_FROM, SMTP_CONNECT_TIMEOUT
• SMTP_SUBJECT, SMTP_BODY, SMTP_CONTENT_TYPE
• SMTP_MAX_ATTACHMENT_BYTES
• SMTP_SYNC_SENT, SMTP_SYNC_SENT_REQUIRED
• SMTP_SENT_IMAP_HOST, SMTP_SENT_IMAP_PORT, SMTP_SENT_IMAP_SSL
• SMTP_SENT_IMAP_USERNAME, SMTP_SENT_IMAP_PASSWORD
• SMTP_SENT_IMAP_MAILBOX, SMTP_SENT_IMAP_FLAGS, SMTP_SENT_IMAP_CONNECT_TIMEOUT
• compatibility fallbacks: IMAP_HOST, IMAP_PORT, IMAP_SSL, IMAP_USERNAME, IMAP_PASSWORD, IMAP_CONNECT_TIMEOUT

Dependency

• Sent-sync mode requires imapclient:

python3 -m pip install imapclient

Error Handling

• Invalid env config exits with code 2.
• Send failure exits with code 1.
• If sync is required (--sent-sync-required or SMTP_SYNC_SENT_REQUIRED=true), sync failure exits with code 1.

References

• references/env.md

Assets

• assets/config.example.env

Scripts

• scripts/smtp_send.py