> ## Documentation Index
> Fetch the complete documentation index at: https://agentmail.manicule.dev/llms.txt
> Use this file to discover all available pages before exploring further.
> For every page in one file, fetch https://agentmail.manicule.dev/llms-full.txt (large).
> To search and read these docs as tools, connect the MCP server at https://agentmail.manicule.dev/api/mcp.
> Every agent surface: https://agentmail.manicule.dev/.well-known/llms-manifest.json

# Attach Human (/api-reference/attach-human)

<!-- agent-signals: reading_time_min: 3 · est_tokens: 1559 · updated: 2026-09-29 -->
Related: [Sign Up](/api-reference/sign-up.md), [Verify](/api-reference/verify.md), [List Inboxes](/api-reference/list-inboxes.md), [Create Inbox](/api-reference/create-inbox.md), [Search Inboxes](/api-reference/search-inboxes.md), [Get Inbox](/api-reference/get-inbox.md)

# Attach Human

`POST /v0/agent/human`

> Attach a human to an unverified agent organization. A 6-digit OTP is sent to the human's email, which you then submit to the verify endpoint.
>
> Use it after signing up without a `human_email`. Once the human is attached, the organization can send email to that human only, and verification lifts the remaining restrictions. For up to 5 minutes after attaching, sends to the human can still be rejected with a `429` daily send limit error while the API key's cached limits catch up. Wait and retry.
>
> Calling it again with the same `human_email` does not rotate the API key. It resends the OTP if it was never delivered, or issues a new one if it expired. While the current OTP is still valid, calling it again keeps that OTP and its attempt count. If all 10 attempts are used up, wait until the OTP expires, 24 hours after it was issued, then call it again for a new one.
>
> Calling it with a different `human_email` replaces the attached human and sends the new human an OTP. An organization can replace its human at most 2 times.
>
> Only available until the organization is verified.
>
> **CLI:**
> ```bash
> agentmail agent attach-human --human-email user@example.com
> ```

Base URL: `https://api.agentmail.to`

Base URL: `https://x402.api.agentmail.to`

Base URL: `https://mpp.api.agentmail.to`

Base URL: `https://api.agentmail.eu`

## OpenAPI

```json
{
  "servers": [
    {
      "url": "https://api.agentmail.to",
      "description": "prod"
    },
    {
      "url": "https://x402.api.agentmail.to",
      "description": "prod-x402"
    },
    {
      "url": "https://mpp.api.agentmail.to",
      "description": "prod-mpp"
    },
    {
      "url": "https://api.agentmail.eu",
      "description": "eu-prod"
    }
  ],
  "security": [
    {
      "Bearer": []
    }
  ],
  "securitySchemes": {
    "Bearer": {
      "type": "http",
      "scheme": "bearer"
    }
  },
  "requestBody": {
    "content": {
      "application/json": {
        "schema": {
          "type": "object",
          "properties": {
            "human_email": {
              "type": "string",
              "description": "Email address of the human who owns the agent. A 6-digit OTP will be sent to this address."
            }
          },
          "required": [
            "human_email"
          ],
          "description": "Request body to attach a human to an agent organization.",
          "title": "AgentAttachHumanRequest"
        }
      }
    }
  },
  "responses": {
    "200": {
      "description": "Response with status 200",
      "content": {
        "application/json": {
          "schema": {
            "type": "object",
            "properties": {
              "human_email": {
                "type": "string",
                "description": "Email address of the attached human."
              },
              "instructions": {
                "type": "string",
                "description": "Next steps for the agent, in plain text."
              }
            },
            "required": [
              "human_email",
              "instructions"
            ],
            "description": "Response after attaching a human to an agent organization.",
            "title": "AgentAttachHumanResponse"
          }
        }
      }
    },
    "400": {
      "description": "Error response with status 400",
      "content": {
        "application/json": {
          "schema": {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "description": "Name of error.",
                "title": "ErrorName"
              },
              "code": {
                "type": "string",
                "description": "Stable, machine-readable error code in snake_case (for example, not_found or missing_permission). Branch on this rather than the message text.",
                "title": "ErrorCode"
              },
              "message": {
                "type": "string",
                "description": "Error message.",
                "title": "ErrorMessage"
              },
              "errors": {
                "description": "Validation errors. Each entry has a path and a message identifying the invalid field."
              },
              "fix": {
                "type": "string",
                "description": "The concrete next action that resolves the error.",
                "title": "ErrorFix"
              },
              "docs": {
                "type": "string",
                "description": "Link to the error reference entry for this code.",
                "title": "ErrorDocs"
              }
            },
            "required": [
              "name",
              "errors"
            ],
            "title": "ValidationErrorResponse"
          }
        }
      }
    },
    "409": {
      "description": "Error response with status 409",
      "content": {
        "application/json": {
          "schema": {
            "type": "object",
            "properties": {
              "name": {
                "type": "string",
                "description": "Name of error.",
                "title": "ErrorName"
              },
              "code": {
                "type": "string",
                "description": "Stable, machine-readable error code in snake_case (for example, not_found or missing_permission). Branch on this rather than the message text.",
                "title": "ErrorCode"
              },
              "message": {
                "type": "string",
                "description": "Error message.",
                "title": "ErrorMessage"
              },
              "fix": {
                "type": "string",
                "description": "The concrete next action that resolves the error.",
                "title": "ErrorFix"
              },
              "docs": {
                "type": "string",
                "description": "Link to the error reference entry for this code.",
                "title": "ErrorDocs"
              }
            },
            "required": [
              "name",
              "message"
            ],
            "title": "ErrorResponse"
          }
        }
      }
    }
  }
}
```