2/COSS - Consensus-Oriented Specification System






Consensus-Oriented Specification System




Pavel Císař <pcisar@users.sourceforge.net>

This document describes a consensus-oriented specification system (COSS) for building interoperable technical specifications. COSS is based on a lightweight editorial process that seeks to engage the widest possible range of interested parties and move rapidly to consensus through working code.

This specification is derived from the COSS specification used by ZeroMQ project.

This is revision 1 of the COSS specification.


Copyright (c) 2008-16 the Editor and Contributors. Copyright (c) 2018 The Firebird Butler Project.

This Specification is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This Specification is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, see http://www.gnu.org/licenses.

Change Process

This Specification is a free and open standard and is governed by the Consensus-Oriented Specification System (COSS) (i.e. by itself).


All ideas and change proposals SHOULD be presented and discussed first in the Firebird Butler forum.


The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC2119.


The primary goal of COSS is to facilitate the process of writing, proving, and improving new technical specifications. A “technical specification” defines a protocol, a process, an API, a use of language, a methodology, or any other aspect of a technical environment that can usefully be documented for the purposes of technical or social interoperability.

COSS is intended to above all be economical and rapid, so that it is useful to small teams with little time to spend on more formal processes.


  • We aim for rough consensus and running code.

  • Specifications are small pieces, made by small teams.

  • Specifications should have a clearly responsible editor.

  • The process should be visible, objective, and accessible to anyone.

  • The process should clearly separate experiments from solutions.

  • The process should allow deprecation of old specifications.

Specifications should take minutes to explain, hours to design, days to write, weeks to prove, months to become mature, and years to replace.

Specifications have no special status except that accorded by the community.


COSS is designed around fast, easy to use communications tools. Primarily, COSS uses a git repository for editing and publishing specifications texts. Additionally, it uses Sphinx (or other similar system) for text processing and a web site for publishing specifications texts in other formats than raw text.

  • The domain is the conservancy for a set of specifications in a certain area.

  • Each domain is implemented as an Internet site with fixed URI (preferably an Internet domain), hosting a git repository and optionally other communications tools.

  • All specifications are stored in repository under /rfc directory.

  • Each specification is a set of pages, together with comments, attached files, and other resources.

  • All texts pages are in reStructuredText markup.

  • Specifications exist as multiple pages, one page per version of the specification (see Branching and Merging, below), with assigned unique incremental number.

  • Specification text is stored in /rfc/<number>/<shortname>.rst file. Thus, we refer to a specification by specifying its number and short name.

  • All related files should be stored in the same directory as the main text file.

  • New versions of the same specification will have new numbers (i.e. will reside in different directories). The syntax for a specification reference is:


    For example, this specification is github.com/FirebirdSQL/Butler/rfc/2/COSS.rst. The short form 2/COSS may be used when referring to the specification from other specifications in the same domain. The RST markup for inserting a hyperlink from the specification in the same domain in this case is:

    :doc:`/rfc/2/COSS`  # specification full name as link text
    :doc:`2/COSS </rfc/2/COSS>`  # specification shortname as link text

Every specification (including branches) carries a different number. Lower numbers indicate more mature specifications, higher numbers indicate more experimental specifications.

COSS Lifecycle

Every specification has an independent lifecycle that documents clearly its current status.

A specification has six possible states that reflect its maturity and contractual weight:


Raw Specifications

All new specifications are raw specifications. Changes to raw specifications can be unilateral and arbitrary. Those seeking to implement a raw specification should ask for it to be made a draft specification. Raw specifications have no contractual weight.

Draft Specifications

When raw specifications can be demonstrated, they become draft specifications. Changes to draft specifications should be done in consultation with users. Draft specifications are contracts between the editors and implementers.

Stable Specifications

When draft specifications are used by third parties, they become stable specifications. Changes to stable specifications should be restricted to cosmetic ones, errata and clarifications. Stable specifications are contracts between editors, implementers, and end-users.

Deprecated Specifications

When stable specifications are replaced by newer draft specifications, they become deprecated specifications. Deprecated specifications should not be changed except to indicate their replacements, if any. Deprecated specifications are contracts between editors, implementers and end-users.

Retired Specifications

When deprecated specifications are no longer used in products, they become retired specifications. Retired specifications are part of the historical record. They should not be changed except to indicate their replacements, if any. Retired specifications have no contractual weight.

Deleted Specifications

Deleted specifications are those that have not reached maturity (stable) and were discarded. They should not be used and are only kept for their historical value. Only Raw and Draft specifications can be deleted.

Editorial control

A specification MUST have a single responsible editor, the only person who SHALL change the status of the specification through the lifecycle stages.

A specification MAY also have additional contributors who contribute changes to it. It is RECOMMENDED to use the C4 process to maximize the scale and diversity of contributions.

The editor is responsible for accurately maintaining the state of specifications and for handling all comments on the specification.

Branching and Merging

Any member of the domain MAY branch a specification at any point. This is done by copying the existing text, and creating a new specification with the same name and content, but a new number. The ability to branch a specification is necessary in these circumstances:

  • To change the responsible editor for a specification, with or without the cooperation of the current responsible editor.

  • To rejuvenate a specification that is stable but needs functional changes. This is the proper way to make a new version of a specification that is in stable or deprecated status.

  • To resolve disputes between different technical opinions.

The responsible editor of a branched specification is the person who makes the branch.

Branches, including added contributions, are derived works and thus licensed under the same terms as the original specification. This means that contributors are guaranteed the right to merge changes made in branches back into their original specifications.

Technically speaking, a branch is a different specification, even if it carries the same name. Branches have no special status except that accorded by the community.

Conflict resolution

COSS resolves natural conflicts between teams and vendors by allowing anyone to define a new specification. There is no editorial control process except that practised by the editor of a new specification. The administrators of a domain (moderators) may choose to interfere in editorial conflicts, and may suspend or ban individuals for behaviour they consider inappropriate.


Where possible editors and contributors are encouraged to:

  • Refer to and build on existing work when possible, especially IETF specifications.

  • Contribute to existing specifications rather than reinvent their own.

  • Use collaborative branching and merging as a tool for experimentation.

Appendix A. Color Coding

It is RECOMMENDED to use color coding to indicate specification’s status. Color coded specifications SHOULD use the following color scheme:

  • raw

  • draft

  • stable

  • deprecated

  • retired

  • deleted

Appendix B. Metainformation

It is RECOMMENDED that specification metadata is specified as a YAML header (where possible) or a separate YAML file. This will enable programmatic access to specification metadata.






specification domain




short name




full name


Consensus-Oriented Specification System






editor name/email


Yurii Rashkovskii yrashk@gmail.com




Pieter Hintjens ph@imatix.com, André Rebentisch andre@openstandards.de, Alberto Barrionuevo abarrio@opentia.es, Chris Puttick chris.puttick@thehumanjourney.net