CIP-88: Ceramic namespace in JSON schemas Source

Author Paul Le Cam
Status Withdrawn
Category RFC
Created 2021-03-01

Simple Summary

Define a standard extension point for Ceramic-specific metadata in a JSON schema.


This CIP defines a reserved namespace for Ceramic-specific metadata in a JSON schema, along with a reference table for standard uses of this namespace.


As commented in the $id cannot be used to define Ceramic-specific extensions as intended in CIP-82.

A previous version of this CIP relied on creating a custom namespace for Ceramic-specific metadata using the non-standard $ceramic key, but it was not compatible with the “strict mode” of the JSON validation library used in Ceramic (AJV). Instead, this CIP relies on the $comment field that is supported by AJV’s strict mode.



A JSON schema property can contain a $comment field, that must be a string starting with cip88::

  type: 'string',
  maxLength: 150,
  $comment: 'ceramic:ref:<schema streamID or commitID>',

Reference table

Type CIP Status
ref StreamID json-schema definition Draft
appendCollection AppendCollection schemas Draft
collectionSlice AppendCollection schemas Draft


Using the $comment property allows to add a metadata string to a schema in a spec-compliant way (compatible with AJV’s strict mode).

The string value must match the following pattern: cip88:<type>[type-specific string].

A unique type, possibly followed by an additional type-specific string, should make it easy to add custom extensions and build tools based on having the $comment value start with cip88:.

Finally, providing a reference table in this CIP should allow for easy discovery and avoid conflicts between extensions.

Backwards Compatibility

CIP-82 and CIP-85 are updated to this new format.


None yet.

Security Considerations

None I’m aware of.

Copyright and related rights waived via CC0.


Please cite this document as:

Paul Le Cam, "CIP-88: Ceramic namespace in JSON schemas," Ceramic Improvement Proposals, no. 88, March 2021. [Online serial]. Available: