API reference · CAIN Identity

Create Identity

POST /fabric/identity/create

Last reviewed 2026-11-06

POST /fabric/identity/create

Create a new cryptographically verifiable identity.

Returns the identity record including a one-time `private_key_b64` field that MUST be securely stored. It is never returned again.

Request body

IdentityCreateRequest (required)

Field	Type	Meaning
`kind` required	string	Identity kind: agent, human, service, mcp_server, tool, sub_agent
`display_name` required	string	min length `1` · max length `255`
`tenant`	string or null	Tenant ID (resolved from API key if omitted)
`capabilities`	array of string or null	Capabilities to grant
`metadata`	object or null
`parent_id`	string or null	Parent identity for delegation
`ttl_seconds`	integer or null	Credential TTL in seconds default `86400`

Responses

Status	Meaning	Body
`200`	Successful Response	object
`401`	The X-API-Key header is missing, or the key is unknown, revoked or replaced.	`Error`
`403`	The key is valid but may not do this (for example an agent key approving its own held action).	`Error`
`422`	Validation Error	`HTTPValidationError`
`429`	Rate limit or monthly quota reached. Wait for the number of seconds in Retry-After when it is sent.	`Error`

Try it

Your API key X-API-Key Remember the key in this tab onlyRequest body application/json

This call changes data in the account the key belongs to.

The request goes from your browser straight to this site. Your key is not stored unless you tick the box, and then only in this tab's session storage.

Code

curl -sS -X POST 'https://cainstudio.online/fabric/identity/create' \
  -H "X-API-Key: $CAIN_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{"kind": "kind", "display_name": "display-name", "ttl_seconds": 86400}'

import json, os, urllib.request

req = urllib.request.Request('https://cainstudio.online/fabric/identity/create', method='POST',
    headers={"X-API-Key": os.environ["CAIN_API_KEY"], "Content-Type": "application/json"},
    data=json.dumps({
      "kind": "kind",
      "display_name": "display-name",
      "ttl_seconds": 86400
    }).encode())
with urllib.request.urlopen(req, timeout=60) as r:
    print(r.status, json.load(r))

const res = await fetch("https://cainstudio.online/fabric/identity/create", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.CAIN_API_KEY!,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "kind": "kind",
    "display_name": "display-name",
    "ttl_seconds": 86400
  }),
});
console.log(res.status, await res.json());

Schemas used

Error · HTTPValidationError · IdentityCreateRequest · ValidationError

← Check Capability · all 30 CAIN Identity calls · Revoke Delegation →

Try CAIN-42 on your own agents

Create a free account and every new account starts with a 30-day trial of the full platform. Or try the sandbox first, with no account at all.

Create a free account → · Try the sandbox · See the whole ecosystem