Lucid Schema API
Define and retrieve the schema for a collection, specifying the fields, types, and constraints for its data items.
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OpenAPI Specification
openapi: 3.2.0
info:
title: Lucid Data Schema API
version: '1.0'
description: The Lucid Data API enables external applications to create, read, update, and delete structured data linked to Lucid documents. Use it to sync data sets, collections, and schemas between your data sources and Lucid diagrams. Authenticate via OAuth 2.0.
contact:
name: Lucid Developer Platform
url: https://developer.lucid.co/
x-documentation: https://developer.lucid.co/reference/data-api
servers:
- url: https://data.lucid.app
tags:
- name: Schema
description: Define and retrieve the schema for a collection, specifying the fields, types, and constraints for its data items.
paths:
/collections/{collectionId}/schema/{fieldDefinitionId}:
get:
summary: Get Field Definition
description: 'Gets a specific existing field definition for a given collection
'
operationId: getFieldDefinition
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to get field definition for
required: true
schema:
type: integer
- name: fieldDefinitionId
in: path
description: ID of field definition to get
required: true
schema:
type: integer
responses:
'200':
description: OK with Field Definition
content:
application/json:
schema:
type: object
properties:
uri:
type: string
description: Link to self
example: https://data.lucid.app/collections/2/schema/4
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
required:
- uri
- name
- fieldType
- collection
- isPrimary
example:
uri: https://data.lucid.app/collections/2/schema/4
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: 'null'
patch:
summary: Update Field Definition
description: 'This endpoint takes a Field Definition, which is used to update the specified field definition. The easiest way to accomplish this is to modify the values in the response from the GET field definition endpoint and send a PATCH request.
'
operationId: updateFieldDefinition
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to update field definition for
required: true
schema:
type: integer
- name: fieldDefinitionId
in: path
description: ID of field definition to update
required: true
schema:
type: integer
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
example:
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: '5'
label: User Friendly Field Name
responses:
'200':
description: OK with Field Definition containing new or updated fields
content:
application/json:
schema:
type: object
properties:
uri:
type: string
description: Link to self
example: https://data.lucid.app/collections/2/schema/4
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
required:
- uri
- name
- fieldType
- collection
- isPrimary
example:
uri: https://data.lucid.app/collections/2/schema/4
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: '5'
label: User Friendly Field Name
delete:
summary: Delete Field Definition
description: 'This removes the field definition from the collection''s schema. This results of this action cannot be undone. The delete will only occur if the user has access to the data source. This action will also remove all data item values associated with the deleted field.
'
operationId: deleteFieldDefinition
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to delete field definition from
required: true
schema:
type: integer
- name: fieldDefinitionId
in: path
description: ID of field definition to delete
required: true
schema:
type: integer
responses:
'200':
description: OK
/collections/{collectionId}/schema:
get:
summary: Get All Field Definitions
description: 'This endpoint returns all field definitions for a given collection if the user has access.
'
operationId: getAllFieldDefinitions
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to get field definitions for
required: true
schema:
type: integer
responses:
'200':
description: OK with Array[Field Definition]
content:
application/json:
schema:
type: array
items:
type: object
properties:
uri:
type: string
description: Link to self
example: https://data.lucid.app/collections/2/schema/4
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
required:
- uri
- name
- fieldType
- collection
- isPrimary
example:
uri: https://data.lucid.app/collections/2/schema/4
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: '5'
label: User Friendly Field Name
patch:
summary: Update Field Definitions
description: 'This endpoint allows updating multiple field definitions at once. The easiest way to accomplish this is to modify the values in the response from the get all field definitions endpoint and send a PATCH request. Changing the values will update existing field definitions within the collection''s schema. Any fields sent without a uri field will result in an addition to the schema if the name field is unique within the schema. Fields cannot be deleted with this endpoint.
'
operationId: updateFieldDefinitions
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to update field definitions for
required: true
schema:
type: integer
requestBody:
required: true
content:
application/json:
schema:
type: array
description: List of field definitions to be added or updated for the collection
items:
type: object
properties:
uri:
type: string
description: Link to self
example: https://data.lucid.app/collections/2/schema/4
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
required:
- uri
- name
- fieldType
- collection
- isPrimary
example:
uri: https://data.lucid.app/collections/2/schema/4
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: '5'
label: User Friendly Field Name
responses:
'200':
description: OK with Array[Field Definition] containing new or updated fields on the collection
content:
application/json:
schema:
type: array
items:
type: object
properties:
uri:
type: string
description: Link to self
example: https://data.lucid.app/collections/2/schema/4
name:
type: string
description: Name of the field
example: Co1B
fieldType:
type: string
description: Stores the type of the field. The type does not affect how the data is interpreted in the Data Service; it is for use on the client side. Valid values include `BOOLEAN`, `STRING`, `NUMBER`, and `ANY`.
example: STRING
collection:
type: string
description: Link to the associated collection
example: https://data.lucid.app/collections/2
isPrimary:
type: boolean
description: Denotes whether the specified field is part of the primary key. The default value is false
example: false
order:
type: string
description: Denotes a default ordering for the fields. This is currently used by the Lucid client to determine the order in which the fields are displayed, unless the context suggests a better ordering.
example: '1'
default:
type: string
description: Default value for this field
example: '5'
label:
type: string
description: Override name for field which is used when displaying to users
example: User Friendly Field Name
required:
- uri
- name
- fieldType
- collection
- isPrimary
example:
uri: https://data.lucid.app/collections/2/schema/4
name: Co1B
fieldType: STRING
collection: https://data.lucid.app/collections/2
isPrimary: false
order: '1'
default: '5'
label: User Friendly Field Name
delete:
summary: Delete Field Definitions
description: 'This endpoint removes only the field definitions provided in the query parameter. The fields in the query parameter must belong to the collection specified. The results of this deletion cannot be undone. The deletion will only occur if the user has access to the data source.
NOTE: If the entire schema is removed then all of the values of each data item are also removed.
'
operationId: deleteFieldDefinitions
tags:
- Schema
security:
- OAuth2:
- data-service.admin
parameters:
- name: collectionId
in: path
description: ID of collection to delete field definitions from
required: true
schema:
type: integer
- name: fields
in: query
description: List of field definition URI's to remove from specified collection
required: true
schema:
type: array
items:
type: string
responses:
'200':
description: OK
components:
securitySchemes:
OAuth2:
type: oauth2
flows:
authorizationCode:
authorizationUrl: https://lucid.app/oauth2/authorize
tokenUrl: https://api.lucid.co/oauth2/token
refreshUrl: https://api.lucid.co/oauth2/token
scopes:
data-service.admin: Scope needed for access to the Data APIs.
x-harvest:
harvested: '2026-08-01'
method: searched
source: https://lucid-developer-docs.readme.io/mcp
note: 'Assembled operation-by-operation from Lucid''s own documentation MCP server (tools list-endpoints + get-endpoint), which returns verbatim OpenAPI 3.0.3 fragments out of the spec Lucid uploaded to its ReadMe hub (/branches/1.4/apis/lucid-data-api.json). Paths, operations, parameters, request bodies, responses, components and securitySchemes are provider content, unmodified. Only the info block is ours: ReadMe''s per-endpoint fragments omit info, so title/description are copied verbatim from the provider''s own list-specs description for this spec.'