Send message
Accepts raw HTML/template content (html); Accepts URL/endpoint input (attachments[].url); Accepts file system path (attachments[].filename); High parameter count (13 properties)
Part of the Agentmail MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use send_message to create or modify resources in Agentmail. 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 send_message 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 Agentmail.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
send_message:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full Agentmail policy for all 11 tools.
Agents calling write-class tools like send_message 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 message. It is categorised as a Write tool in the Agentmail 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 send_message. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Agentmail MCP server.
send_message 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 send_message 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 send_message. 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.
send_message is provided by the Agentmail MCP server (agentmail-mcp). 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