---
title: "Call the sendMessage MCP tool"
method: POST
path: "/api/v1/actions/sendMessage"
tags: ["Actions"]
---

# Call the sendMessage MCP tool

`POST /api/v1/actions/sendMessage`

## Request

- Base URL: `https://app.reachium.io`
- URL: `https://app.reachium.io/api/v1/actions/sendMessage`
- Auth: HTTP bearer

Send a LinkedIn direct message to a lead who is already a 1st-degree connection of one of this workspace's LinkedIn accounts, starting a new conversation if none exists. Use sendReply instead when you already have a chat_id. Refuses non-connections (it can never cold-DM). LAUNCH action, two-step: first call returns a preview and confirm_token; re-send with the same lead_id and text plus confirm_token to send. Draws from the same daily per-account message budget as campaigns. If the workspace has several accounts and none has a chat or invite history with the lead, pass linkedin_account_id (from getLinkedInAccounts).

Called through the Actions bridge: the response is that tool's own result, wrapped as `{ data: <tool result> }` under HTTP 200. Billing, daily-cap, and confirm-step outcomes are embedded INSIDE `data`, never remapped to an HTTP status (see the templated `/api/v1/actions/{toolName}` operation above for the full protocol, and `x-mcp-actions` for this tool's machine-readable scope/cap/confirm_behavior fields). Authentication, request-shape, and optional idempotency-protocol failures still use their documented non-200 statuses.

## Headers

- `Idempotency-Key` string

## Request body

- object
  - `operation_id` string: Unique logical send ID: reuse for retries, change only for an intentional new message.
  - `lead_id` string, uuid, required: The lead to message (from findLeads / getCampaignLeads).
  - `linkedin_account_id` string, uuid: Which of your LinkedIn accounts sends. Optional when it can be inferred.
  - `text` string, required: The message text. No em dashes (arrows are fine).
  - `confirm_token` string: From the preview response. Re-send with the same lead_id and text to execute.

## Response `200`

The result of calling this tool.

- object
  - `data` unknown, required
  - `error` unknown, required

## Other responses

- `400`: The request body was not a JSON object (code invalid_request), or Idempotency-Key is malformed (code invalid_idempotency_key).
- `401`: Missing or invalid API key. Send `Authorization: Bearer rmcp_...` (code unauthorized).
- `403`: This tool is out of the key’s granted scope (code insufficient_scope).
- `409`: This Idempotency-Key has an unresolved in-flight or ambiguous result (code request_in_flight). Reconcile before using a new key.
- `422`: This Idempotency-Key was already used with a different request body (code idempotency_key_reuse).
- `429`: Rate limited: shared `mcp:ip:{ip}` (600/60s) or `mcp:key:{keyId}` (120/60s) bucket, the SAME buckets the MCP endpoint uses (code rate_limited).
- `500`: Unhandled server error (code internal_error).

---

[API](https://skmtc.dev/reachium/apis/reachium-api.md) · [All operations](https://skmtc.dev/reachium/apis/reachium-api/llms.txt) · [OpenAPI document](https://skmtc.dev/reachium/apis/reachium-api/revisions/11682826692b?raw)