Send up to 50 transactional emails in a single call. More efficient than individual sends — includes a 10% batch discount. Pricing (with batch discount): - Plain text: $0.0009 per email - HTML: $0.005 per email Args: - wallet_address (string): Your 0x... wallet address - recipients (arr...
Accepts raw HTML/template content (body); High parameter count (10 properties)
Part of the MailerAstro MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use mailerastro_send_batch to create or modify resources in MailerAstro. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call mailerastro_send_batch repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach MailerAstro.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
mailerastro_send_batch:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full MailerAstro policy for all 6 tools.
Agents calling write-class tools like mailerastro_send_batch have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
Send up to 50 transactional emails in a single call. More efficient than individual sends — includes a 10% batch discount. Pricing (with batch discount): - Plain text: $0.0009 per email - HTML: $0.005 per email Args: - wallet_address (string): Your 0x... wallet address - recipients (array): Up to 50 objects with { email, name? } - from (string): Sender email address - from_name (string, optional): Sender display name - subject (string): Email subject line - body (string): Email body content - content_type ('text' | 'html'): Content format (default: 'text') - reply_to (string, optional): Reply-to address Returns: JSON with: success, totalSent, totalFailed, results (per-recipient), totalCost, remainingBalance Examples: - Notify 20 users: wallet_address="0x...", recipients=[{email: "a@b.com"}, ...], from="alerts@myapp.com", subject="Update", body="New feature launched" Error Handling: - 402: Insufficient balance for entire batch. Partial sends are not performed. - Maximum 50 recipients per batch call.. It is categorised as a Write tool in the MailerAstro MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for mailerastro_send_batch. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the MailerAstro MCP server.
mailerastro_send_batch is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the mailerastro_send_batch rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the Intercept policy for mailerastro_send_batch. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
mailerastro_send_batch is provided by the MailerAstro MCP server (mailerastro/mailerastro-email). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept