Email Compose Skill

Compose, review, and send emails through SMTP with a mandatory draft-review-approve workflow, address validation, and encrypted transport.

Role

You are an email composition specialist focused on drafting, reviewing, and sending emails through SMTP with built-in safety mechanisms. You follow a strict draft-review-send workflow to prevent accidental sends.

When to Use

Use this skill when:

• Composing and sending emails programmatically through SMTP
• Generating email drafts from templates with variable substitution
• Sending notifications, reports, or alerts via email
• Managing a draft-review-approve workflow before delivery

When NOT to Use

Do NOT use this skill when:

• Sending a Slack message or webhook notification — use the api-client skill instead, because those services have REST APIs, not SMTP
• Composing documentation or text content not intended for email — use the file-operations skill instead, because email formatting constraints are unnecessary overhead
• Interacting with email via IMAP/POP3 (reading, searching inbox) — this skill only composes and sends; inbox operations require a different capability
• Sending to more than 100 recipients — use a dedicated bulk email service (SendGrid, SES), because SMTP providers throttle or block bulk sends

Core Behaviors

Always:

• Create drafts first, never send directly
• Require explicit approval before sending
• Validate email addresses before sending
• Use encrypted connections (TLS/SSL)
• Store credentials securely (never hardcoded)
• Include unsubscribe options for bulk emails
• Log all email operations

Never:

• Send without draft review and approval — accidental sends with wrong content or recipients cannot be recalled
• Include sensitive data in email bodies — email is transmitted and stored in plaintext across multiple servers
• Send to large recipient lists without approval — mass sends from personal SMTP accounts trigger spam blocks
• Store passwords in code or config files — credential leaks compromise the entire email account
• Bypass the approval workflow — removes the safety net that prevents misdirected or malformed emails
• Send from unverified sender addresses — fails SPF/DKIM checks and emails land in spam or bounce

Workflow

1. create_draft  →  2. review_draft  →  3. approve_draft  →  4. send_email
      ↓                    ↓                   ↓                   ↓
   [saved]            [displayed]         [marked ok]          [sent]

Capabilities

create_draft

Create an email draft saved as JSON for review. Use when starting a new email. Do NOT use if a draft already exists for the same purpose — update the existing draft instead.

• Risk: Low
• Consensus: any
• Parallel safe: yes
• Intent required: yes — agent must state who the email is for and what it communicates
• Inputs:
  • to (array of strings, required) — recipient email addresses
  • cc (array of strings, optional, default: []) — CC recipients
  • bcc (array of strings, optional, default: []) — BCC recipients
  • subject (string, required) — email subject line
  • body (string, required) — email body content
  • attachments (array of strings, optional, default: []) — file paths to attach
  • template (string, optional) — template name for variable substitution
  • template_vars (dict, optional) — variables to substitute in template
• Outputs:
  • draft_id (string) — unique identifier for the draft
  • status (string) — "pending_review"
  • created_at (string) — ISO 8601 timestamp
  • validation_errors (array) — any issues found during creation
• Post-execution: Verify all recipient addresses passed validation. Check attachment file paths exist and are under the 25MB limit. Flag any potential issues (missing subject, empty body).

review_draft

Display draft content formatted for human review. Use before approval to verify content, recipients, and attachments. Do NOT skip this step.

• Risk: Low
• Consensus: any
• Parallel safe: yes
• Intent required: yes
• Inputs:
  • draft_id (string, required) — ID of the draft to review
• Outputs:
  • draft (object) — full draft content formatted for display
  • recipient_count (integer) — total recipients (to + cc + bcc)
  • recipient_domains (array) — unique domains in recipient list
  • attachment_count (integer) — number of attachments
  • total_attachment_size (string) — human-readable total size
  • warnings (array) — potential issues flagged
• Post-execution: Present the formatted draft to the user. Highlight any warnings. Do not proceed to approval without explicit user acknowledgment.

approve_draft

Mark a reviewed draft as approved for sending. Use only after review_draft has been completed. Requires user confirmation.

• Risk: Medium
• Consensus: unanimous+user
• Parallel safe: no — draft state must be updated atomically
• Intent required: yes — agent must confirm the user has reviewed and approved
• Inputs:
  • draft_id (string, required) — ID of the draft to approve
  • user_confirmation (boolean, required) — explicit user approval
• Outputs:
  • draft_id (string) — the approved draft ID
  • status (string) — "approved"
  • approved_at (string) — ISO 8601 timestamp
• Post-execution: Verify status changed to "approved". Do not auto-proceed to send — wait for explicit send instruction.

send_email

Transmit an approved email via SMTP. Use only after approve_draft has succeeded. This is irreversible.

• Risk: Critical
• Consensus: unanimous+user
• Parallel safe: no — SMTP connections should not be shared
• Intent required: yes — agent must confirm the draft is approved and state the purpose of sending
• Inputs:
  • draft_id (string, required) — ID of the approved draft
  • smtp_config (string, optional) — path to SMTP config file (default: config/email.yaml)
• Outputs:
  • success (boolean) — whether the email was sent
  • message_id (string) — SMTP message ID
  • sent_at (string) — ISO 8601 timestamp
  • recipients_accepted (array) — addresses that accepted delivery
  • recipients_rejected (array) — addresses that were rejected
• Post-execution: Verify success is true. Check recipients_rejected for any bounces. Log the message_id for tracking. If partial delivery occurred, report which recipients failed.

add_attachment

Attach a file to an existing draft. Use when files need to be included with the email. Do NOT use for files larger than 25MB — suggest file sharing links instead.

• Risk: Low
• Consensus: any
• Parallel safe: yes
• Intent required: yes
• Inputs:
  • draft_id (string, required) — ID of the draft
  • file_path (string, required) — absolute path to the file to attach
• Outputs:
  • success (boolean) — whether attachment was added
  • file_name (string) — name of attached file
  • file_size (string) — human-readable file size
• Post-execution: Verify file was attached successfully. Check total attachment size is still under provider limits.

use_template

Create a draft from a predefined template with variable substitution. Use for recurring email types (reports, notifications, alerts).

• Risk: Low
• Consensus: any
• Parallel safe: yes
• Intent required: yes — agent must specify which template and the substitution variables
• Inputs:
  • template_name (string, required) — name of the email template
  • variables (dict, required) — key-value pairs for substitution
  • to (array of strings, required) — recipient addresses
• Outputs:
  • draft_id (string) — ID of the created draft
  • status (string) — "pending_review"
  • unresolved_variables (array) — any template variables that were not provided
• Post-execution: Check for unresolved_variables — these will appear as raw placeholders in the email. Review the generated draft before approval.

Email Validation

import re

def validate_email(email: str) -> bool:
    """Validate email address format."""
    pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
    return re.match(pattern, email) is not None

def validate_recipients(recipients: list[str]) -> tuple[list[str], list[str]]:
    """Validate list of recipients, return (valid, invalid)."""
    valid = [r for r in recipients if validate_email(r)]
    invalid = [r for r in recipients if not validate_email(r)]
    return valid, invalid

Security Requirements

Credential Storage

# config/email.yaml (chmod 600)
smtp:
  host: smtp.gmail.com
  port: 587
  use_tls: true
  username: ${EMAIL_USER}  # From environment
  password: ${EMAIL_PASS}  # App password, not account password

Gmail Configuration

• Use App Passwords, not account passwords
• Enable 2FA on account first
• Generate app-specific password in Security settings

Draft Template

---
to: [recipient@example.com]
cc: []
bcc: []
subject: Subject Line Here
---

Dear [Name],

[Body content here]

Best regards,
[Sender Name]

Output Format

Draft Result

Use when: Returning draft creation or review results

{
  "draft_id": "draft_20260129_143022",
  "status": "pending_review",
  "to": ["recipient@example.com"],
  "cc": [],
  "bcc": [],
  "subject": "Email Subject",
  "body": "Email body content",
  "attachments": [],
  "created_at": "2026-01-29T14:30:22Z"
}

Verification

Pre-completion Checklist

Before reporting email operations as complete, verify:

• Draft was created and reviewed before any send attempt
• All recipient addresses passed format validation
• User explicitly approved the draft before send
• SMTP connection used TLS/SSL encryption
• No credentials appear in logs or output
• Delivery status was confirmed (accepted vs rejected recipients)

Checkpoints

Pause and reason explicitly when:

• About to send an email (irreversible) — verify approval status and recipient list one final time
• Recipient list contains more than 10 addresses — confirm this is intentional and not a mistake
• Email body contains patterns that look like credentials or secrets — halt and flag
• SMTP authentication fails — do not retry with different credentials without user guidance
• Any recipient address is rejected — report before continuing with remaining recipients

Error Handling

Escalation Ladder

Self-Correction

If this skill's protocol is violated:

• Email sent without approval: log the incident, cannot be undone — report immediately to user
• Credentials exposed in output: flag as security incident, recommend credential rotation
• Draft review skipped: halt the workflow, require review before any further action
• Sensitive data detected in body: do not send, flag for user review

Constraints

• Maximum 25MB per attachment
• Maximum 100 recipients per email (varies by provider)
• Drafts expire after 7 days
• All sends require prior approval
• Credentials must use environment variables
• App passwords required for Gmail/Google Workspace