---
title: "Add another agent to an unclaimed workspace"
method: POST
path: "/v1/signup/agents"
tags: ["Agent self-signup"]
---

# Add another agent to an unclaimed workspace

`POST /v1/signup/agents`

## Request

- Base URL: `https://api.agentboxd.com`
- URL: `https://api.agentboxd.com/v1/signup/agents`
- Auth: HTTP bearer

`{ kind?: "mailbox" | "identity", expires_at? }` → `201 { api_key, api_key_expires_at, kind, workspace, inbox, identity, next_steps }`. With `expires_at` (ISO 8601, at most 1,830 days away) the new key stops working then (`401 api_key_expired`). Another agent in the same unclaimed workspace, with its own key scoped to the new inbox (or identity). Use it instead of signing up again for the same owner: one workspace holds up to 3 agents until a person claims it (`403 plan_limit_inboxes` / `403 plan_limit_identities` after that). Any key of the workspace (`inboxes:read`). `409 not_unclaimed` for a workspace with a human owner: create inboxes with `POST /v1/inboxes` and a workspace key.

Permission: `inboxes:read`.

## Request body

- object
  - `kind` 'mailbox' | 'identity'
  - `expires_at` string, date-time, nullable

## Response `200`

OK

- object

## Other responses

- `4XX`: Error
- `5XX`: Error

---

[API](https://skmtc.dev/agentboxd/apis/agentboxd-api.md) · [All operations](https://skmtc.dev/agentboxd/apis/agentboxd-api/llms.txt) · [OpenAPI document](https://skmtc.dev/agentboxd/apis/agentboxd-api/revisions/ee7b079f0e97?raw)