---
title: "Create or replace a creature by id"
method: PUT
path: "/api/v2/creature/{id}"
tags: ["Creature"]
---

# Create or replace a creature by id

`PUT /api/v2/creature/{id}`

## Request

- Base URL: `https://www.onlyworlds.com`
- URL: `https://www.onlyworlds.com/api/v2/creature/{id}`
- Auth: API key in header `API-Key` and API key in header `API-Pin`

## Path parameters

- `id` string, uuid, required

## Headers

- `X-OW-Agent` string

## Request body

- CreatureWrite: A full creature write (POST creates; PUT creates or fully replaces, resetting omitted fields to empty). Any key that is neither a field below nor an extension field (atlas_*, shadow_*, x_*) is a 422, including the server-managed type, created_at, updated_at and change_seq.
  - `id` string, uuid: POST: optional client-minted id (any RFC 4122 UUID; the server mints a UUIDv7 otherwise). PUT/PATCH: ignored, the path id wins.
  - `name` string, nullable, required: Name of the element. null stores ''.
  - `description` string, nullable: Any kind of details about the element. null stores ''.
  - `supertype` string, nullable: The top level category to which the element belongs. null stores ''.
  - `subtype` string, nullable: The sub level category through which the element is further classified. null stores ''.
  - `image_url` string, nullable: URL to an image representing the element. null stores ''.
  - `appearance` string, nullable: Visual description of the creature. null stores ''.
  - `habits` string, nullable: Typical behaviors, instincts, or recurring actions the creature tends to display. null stores ''.
  - `demeanor` string, nullable: The emotional tone or attitude the creature conveys through posture, expression, or aggression. null stores ''.
  - `status` string, nullable: Current situation or classification of the creature. null stores ''.
  - `weight` integer, nullable: Approximate or exact weight of the creature, in the world's mass unit (World mass_unit).
  - `height` integer, nullable: Approximate height of the creature, in the world's length unit (World length_unit).
  - `birth_date` integer, nullable: The time of the creature's birth, recorded in the world's defined TIME unit.
  - `challenge_rating` integer, nullable: Difficulty or threat level of the creature in a gameplay context.
  - `hit_points` integer, nullable: Total health or durability value in combat.
  - `armor_class` integer, nullable: Defense rating against physical attacks or effects.
  - `speed` integer, nullable: Typical movement speed, in the world's distance unit (World distance_unit) per round.
  - `location` string, uuid, nullable: Specific location where the creature is currently found or most associated with. Links a Location: an existing one in this world.
  - `zone` string, uuid, nullable: Larger area or region commonly inhabited or currently claimed by the creature. Links a Zone: an existing one in this world.
  - `species` string[], nullable: Species this creature belongs to. Links Species elements; replaces the whole list (null is the same as []). Every id must name an existing one in this world.
  - `traits` string[], nullable: Traits that influence the creature's behavior, capabilities, or appearance. Links Trait elements; replaces the whole list (null is the same as []). Every id must name an existing one in this world.
  - `abilities` string[], nullable: Innate or learned abilities the creature can perform or activate. Links Ability elements; replaces the whole list (null is the same as []). Every id must name an existing one in this world.
  - `languages` string[], nullable: Languages the creature can understand, speak, or otherwise use to communicate. Links Language elements; replaces the whole list (null is the same as []). Every id must name an existing one in this world.
  - `actions` string[], nullable: Combat or tactical abilities the creature can perform or use. Links Ability elements; replaces the whole list (null is the same as []). Every id must name an existing one in this world.
  - `world` unknown
  - `created_by` unknown
  - `changed_by` unknown
  - `changed_via` unknown

## Response `200`

Replaced: the full element.

- Creature: A creature as the API returns it. Single links are an id or null, multi links an array of ids; extension fields appear inline. `?fields=` returns only the named keys, and `?expand=` replaces the named links' ids with ElementStub objects.
  - `type` 'creature', required
  - `id` string, uuid, required
  - `name` string, required: Name of the element.
  - `description` string, required: Any kind of details about the element.
  - `supertype` string, required: The top level category to which the element belongs.
  - `subtype` string, required: The sub level category through which the element is further classified.
  - `image_url` string, required: URL to an image representing the element.
  - `appearance` string, required: Visual description of the creature.
  - `habits` string, required: Typical behaviors, instincts, or recurring actions the creature tends to display.
  - `demeanor` string, required: The emotional tone or attitude the creature conveys through posture, expression, or aggression.
  - `status` string, required: Current situation or classification of the creature.
  - `weight` integer, nullable, required: Approximate or exact weight of the creature, in the world's mass unit (World mass_unit).
  - `height` integer, nullable, required: Approximate height of the creature, in the world's length unit (World length_unit).
  - `birth_date` integer, nullable, required: The time of the creature's birth, recorded in the world's defined TIME unit.
  - `challenge_rating` integer, nullable, required: Difficulty or threat level of the creature in a gameplay context.
  - `hit_points` integer, nullable, required: Total health or durability value in combat.
  - `armor_class` integer, nullable, required: Defense rating against physical attacks or effects.
  - `speed` integer, nullable, required: Typical movement speed, in the world's distance unit (World distance_unit) per round.
  - `location` string, uuid, nullable, required: Specific location where the creature is currently found or most associated with. A Location's id.
  - `zone` string, uuid, nullable, required: Larger area or region commonly inhabited or currently claimed by the creature. A Zone's id.
  - `species` string[], required: Species this creature belongs to. Species ids.
  - `traits` string[], required: Traits that influence the creature's behavior, capabilities, or appearance. Trait ids.
  - `abilities` string[], required: Innate or learned abilities the creature can perform or activate. Ability ids.
  - `languages` string[], required: Languages the creature can understand, speak, or otherwise use to communicate. Language ids.
  - `actions` string[], required: Combat or tactical abilities the creature can perform or use. Ability ids.
  - `created_at` string, date-time, required
  - `updated_at` string, date-time, required
  - `change_seq` integer, required: The world change sequence at this element's last write.
  - `created_by` string, uuid, nullable, required: The world membership that created this element, or null when the world's owner did.
  - `changed_by` string, uuid, nullable, required: The world membership that last changed this element, or null when the world's owner (or the server) did, or no write has touched it since doors were recorded.
  - `changed_via` 'seat' | 'mcp' | 'declared' | 'api' | 'v1' | 'sync' | 'server' | 'null', nullable, required: The door of the last change: `seat` (an agent seat), `mcp` (the MCP server), `declared` (the request sent an X-OW-Agent header), `api`, `v1`, `sync` (the mobile app's sync) or `server` (the server, on its own behalf). The first three mean an agent made it. Null: no write since doors were recorded.
  - `known_of` true: Present, and true, only on an element this reader knows of but does not see whole: a guest or player reaches it only because its own Character's sheet links to it (one step out). Such a row keeps `id`, `type`, `name`, `description`, `supertype`, `subtype`, `image_url`, `created_at`, `updated_at` and `change_seq`, and its type's public fields (none for a creature); every other field reads as unset (text "", numbers and single links null, multi links [], `created_by`, `changed_by` and `changed_via` null, no extension fields), its files are 404, and search matches only what it keeps. Absent: the element is whole. Any other grant (it names the reader's Character, the reader knows it, it is on the roster, the reader made it) makes it whole; a hidden element is never even a stub, whatever its public fields. Read-only: a write carrying `known_of` is refused (`known_of_not_writable`).

## Other responses

- `201`: Created: the full element.
- `400`: A link names an element that does not exist in this world (code invalid_link).
- `401`: Missing, invalid or revoked credential, or a wrong PIN (authentication_error; code key_revoked for a revoked key, invalid_credentials otherwise).
- `403`: The credential is valid but lacks the scope: a read key on a write route (permission_error). Or a contributor or guest key changed, replaced, relinked or deleted an element someone else created (code not_author); those members change only their own, and, for an agent seat the owner gave a Character, that Character (never deleting it).
- `409`: The id is held by an element in another world (id_conflict).
- `422`: Invalid request: unknown or read-only field, bad value, unknown query parameter, over-long text, extensions over the size cap (invalid_request); `param` names the culprit.
- `429`: Too many failed PIN attempts; see the Retry-After header (rate_limited). Or too many requests: over the request budget (code too_many_requests, type rate_limited): 300 requests a minute per key or account token, 60 a minute per address for a request with neither. Retry after the Retry-After header's seconds.
- `503`: The server is busy: every request slot stayed full for 10 s (code server_busy, type api_error). Retry after the Retry-After header's seconds.

## Changes

- **2026-10-20** `78df39c4c62e`: 7 warning
  - added the new `known_of_not_writable` enum value to the `error/code` response property for the response status `400`
  - added the new `known_of_not_writable` enum value to the `error/code` response property for the response status `401`
  - added the new `known_of_not_writable` enum value to the `error/code` response property for the response status `403`
  - added the new `known_of_not_writable` enum value to the `error/code` response property for the response status `409`
  - …3 more
- **2026-10-20** `4dd5b1cd0687`: 14 warning, 2 info
  - added the new `character_taken` enum value to the `error/code` response property for the response status `400`
  - added the new `character_taken` enum value to the `error/code` response property for the response status `401`
  - added the new `character_taken` enum value to the `error/code` response property for the response status `403`
  - added the new `character_taken` enum value to the `error/code` response property for the response status `409`
  - …12 more

[Operation history](https://skmtc.dev/onlyworlds/apis/onlyworlds-api/changes/api/v2/creature/:id/put.md)

---

[API](https://skmtc.dev/onlyworlds/apis/onlyworlds-api.md) · [All operations](https://skmtc.dev/onlyworlds/apis/onlyworlds-api/llms.txt) · [OpenAPI document](https://skmtc.dev/onlyworlds/apis/onlyworlds-api/revisions/1752622ae8ce?raw)