# send_flow_message

Returns ok/sentTo or a delivery/eligibility error.

## Purpose

Send ONE pending_review draft (optionally with edited subject/body/recipient). This emails a real person — show the user the draft and get explicit approval first unless they already said to send in bulk. The merchant's flow then continues.

## Credentials and scope

Owner workspace credential. The credential determines tool visibility. For tools with appId, use the HeyCrust app UUID from list_apps; the dashboard app selector does not supply MCP arguments for you.

## Inputs

- `messageId`: required; integer; maximum: 9007199254740991
- `toEmail`: optional; string; format: email
- `subject`: optional; string
- `body`: optional; string

## Example request

The identifiers and merchant are fictional. Replace them with records returned for your own workspace; this example is schema-checked, not a promise that the fictional record exists.

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "send_flow_message",
    "arguments": {
      "messageId": 123
    }
  }
}
```

POST this JSON to `https://heycrust.com/api/mcp` with `Content-Type: application/json` and `Authorization: Bearer <YOUR_CREDENTIAL>`. The tool result normally contains JSON encoded as text in `result.content`; inspect JSON-RPC errors and `result.isError` before using it.

## Result

Returns ok/sentTo or a delivery/eligibility error. Provider acceptance does not prove that a recipient read the email.

## Effects and verification

Sends a real email for an eligible pending-review draft and resumes its Flow. Read the pending draft and obtain approval before calling this tool. An accepted schema is not proof of a valid draft or a working sender.

## Troubleshooting

A missing tool can mean that the credential lacks its catalog or required scopes. Invalid arguments are different from unavailable source data or a record outside the workspace. A handler can return a business error even when the argument schema is valid. Read [MCP overview](/docs/mcp) and [Help](/docs/help).