Update a custom tool. Omitted fields remain unchanged; titles must remain unique within the workspace.
OAuth scope: api:write.
PATCH
/api/v2/custom-tools/{customToolId}X-API-Key<token>
Your Sim API key, personal or workspace-scoped. Generate one under Settings, then API Keys. Operations that reject workspace keys say so in their own description.
In: header
Path Parameters
customToolId*string
Unique custom tool identifier.
Length
1 <= lengthRequest Body
application/json
Custom tool fields to change; at least one editable field is required.
TypeScript Definitions
Use the request body type in TypeScript.
Response Body
application/json
application/json
application/json
application/json
application/json
application/json
application/json
application/json
application/json
application/json
application/json
curl -X PATCH "https://www.sim.ai/api/v2/custom-tools/string" \ -H "X-API-Key: YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "workspaceId": "a91c4b2e-6d3f-4e8a-b5c7-0d9e2f1a8c64", "code": "return { ok: false }" }'{
"data": {
"id": "V1StGXR8Z5jdHi6BmyT",
"title": "lookup_order",
"schema": {
"type": "function",
"function": {
"name": "lookup_order",
"description": "Look up an order by id",
"parameters": {
"type": "object",
"properties": {
"orderId": {
"type": "string"
}
},
"required": [
"orderId"
]
}
}
},
"code": "return { ok: false }",
"createdAt": "2026-06-01T09:14:00.000Z",
"updatedAt": "2026-06-20T14:02:11.000Z"
}
}{
"error": {
"code": "BAD_REQUEST",
"message": "Invalid request"
}
}{
"error": {
"code": "UNAUTHORIZED",
"message": "Authentication required"
}
}{
"error": {
"code": "FORBIDDEN",
"message": "Insufficient workspace permissions",
"details": {
"code": "INSUFFICIENT_WORKSPACE_ROLE"
}
}
}{
"error": {
"code": "NOT_FOUND",
"message": "Not found"
}
}{
"error": {
"code": "CONFLICT",
"message": "The request conflicts with the current state of the resource"
}
}{
"error": {
"code": "PAYLOAD_TOO_LARGE",
"message": "Request body is too large"
}
}{
"error": {
"code": "UNSUPPORTED_MEDIA_TYPE",
"message": "Request body must be sent as application/json"
}
}{
"error": {
"code": "RATE_LIMITED",
"message": "API rate limit exceeded",
"details": {
"retryAfter": "2026-01-01T00:00:30.000Z"
}
}
}{
"error": {
"code": "INTERNAL_ERROR",
"message": "Internal server error"
}
}{
"error": {
"code": "SERVICE_UNAVAILABLE",
"message": "Service temporarily unavailable"
}
}