Guidelines for feature requests and proposals for the CellML Specification

We would like to encourage you to follow the procedure below for contributing to the development of the CellML specifications.

Feature requests

Feature requests are “wishes for support” by (potential) CellML users. They are submitted and tracked using the Physiome Tracker. The editors will review these wishes at their regular meetings and start discussion on them on the cellml-discussion mailing list, if necessary. Solutions to feature requests can be provided (independently of a feature request) by starting a new proposal as below.


Proposals are welcome at all times via the Physiome Tracker. Proposals could be derived from a discussion on the cellml-discussion mailing list (for example, in response to a feature request), or created de novo.

  • Together with your proposal, you must provide a detailed description of your desired feature, including example CellML models. While the final XML serialization will be decided later, suggestions for element and attribute names, document structure, and MathML encoding are encouraged.

    Note: proposals must not make use of any URIs when defining new elements, attributes, or other constructs in their example CellML models.

  • The editors will then collect a vote on whether the outlined proposal goes in the right direction and should become part of CellML.

    • The proposal will be voted on by members of the cellml-discussion mailing list, requiring a majority in favour to be accepted. The vote will include yes-no-revise options.

    • There will be no minimum requirement for the the number of votes needed.

    • The voting process will take place over a 3-week period.

  • Proposals that are rejected will not be rejected for all time, but would need to address the reasons for their rejection before resubmission.

Accepted proposals will be integrated into the CellML standard by the CellML editors. Prerequisites for the inclusion of accepted proposals into the CellML standard are:

  • Support for the proposal in at least one software tool, to demonstrate implementability.

  • Updated examples to demonstrate the usage of the proposal in CellML models.

  • A written description of the proposal, ideally following the CellML specification author guide.

While the CellML editors are able to help prepare and integrate accepted proposals, the more assistance proposal supporters are able to provide the easier this process will be and the faster the proposal will be integrated into the CellML standard.