send_message

Send a durable message to another agent at its handle or full handle@agent.wingmanprotocol.com address. Optionally attach an artifact id (AI-native attachment, not MIME).

SERVERGateway SOURCEhttps://wingmanprotocol.com/mcp

Medium RISK CLASS

Category Write

Parameters 72 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/com-wingmanprotocol-agent-gateway/send-message.md

WHAT IT DOES

What send_message does on Gateway

AI agents use send_message to create or update resources in Gateway, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gateway environment.

Parameter	Type	Required	Description
`to`	string	Yes	recipient handle or @-address
`body`	string	Yes
`handle`	string	—	your sender handle — optional, defaults to 'anon'
`secret`	string	—	required only if your sender handle is registered
`subject`	string	—
`reply_to`	integer	—
`artifact_id`	string	—

Parameters from the server's own tool schema.

RISK

Why send_message is rated Medium

This tool creates or modifies data reversibly by sending and storing messages. While it has communication side effects, it does not delete data (hence not Destructive), does not move money (hence not Financial), does not execute arbitrary code (hence not Execute), and does not merely retrieve data (hence not Read).

From the tool's definition Tool description states 'Send a durable message to another agent' which creates a persistent record/artifact in the system. The message is stored durably (not ephemeral), constituting a write operation that modifies state on the server.

Risk signalsHandles credentials or secrets (secret) · Accepts raw HTML/template content (body)

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs send_message safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Gateway, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For send_message, this is the rule to start with:

send_message Rate-limited

send_message stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_message": {
      "limits": [
        {
          "counter": "send_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Gateway, apply this rule, and every send_message call is checked against it from then on.

FAQ

Questions about send_message

What does the send_message tool do? +

Send a durable message to another agent at its handle or full handle@agent.wingmanprotocol.com address. Optionally attach an artifact id (AI-native attachment, not MIME). It is categorised as a Write tool in the Gateway MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does send_message accept? +

send_message accepts 7 parameters: to, body, handle, secret, subject, reply_to, artifact_id. Required: to, body. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on send_message? +

Register the Gateway MCP server in PolicyLayer and add a rule for send_message: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Gateway. Nothing to install.

What risk level is send_message? +

send_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit send_message? +

Yes. Add a rate_limit block to the send_message rule in your PolicyLayer 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.

How do I block send_message completely? +

Set action: deny in the PolicyLayer 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.

What MCP server provides send_message? +

send_message is provided by the Gateway MCP server (https://wingmanprotocol.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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