Welcome to the unclassified repository for the Universal Command and Control (C2) Interface (UCI) Standard, a government‑owned, non‑proprietary open architecture specification enabling mission‑level machine‑to‑machine C2 across heterogeneous systems. This repository contains the complete UCI Definition & Documentation (D&D) set for UCI Version 2.5, released 22 January 2026.
The UCI standard provides a common message definition for performing mission operations and enables C2 coordination across sensors, vehicles, data products, and software components.
Note
The United States Air Force is experimenting with releasing unclassified standards on https://gitlab.com/modular-af/ and https://github.com/modular-af/. We welcome constructive feedback on how we can improve this approach. These repositories currently focus exclusively on the technical standard and documentation. Example "hello world" software is forthcoming.
The UCI standard defines a messaging architecture that enables interoperable, mission‑level command and control across multi‑domain systems — air, land, sea, space, and cyberspace. It includes:
- Message definitions (via the UCI Schema)
- Interaction patterns (via the Normalized Interface Specification)
- Schema design rules (via the Schema Style & Design Specification)
- Compliance expectations for adopting programs
The UCI standard supports both command/control messages and situational awareness/data messages. It is intentionally technology‑agnostic — it does not prescribe hardware, operating system, encoding, or transport protocols, allowing programs to adopt modern technologies without breaking interoperability.
The UCI standard is designed to support the need for rapid, interoperable, multi‑domain mission execution. The standard emphasizes:
- Interoperability Across Platforms: UCI enables seamless data exchange across heterogeneous systems.
- Modularity & Flexibility: Programs can adopt only the messages they need using Message Sets and Program Schemas.
- Technology Independence: UCI avoids locking programs into specific encodings or transports.
- Support for Modern Mission Needs: Multi‑domain operations, machine‑to‑machine C2, situational awareness, secure messaging
- Reduced Integration Risk: Common message definitions reduce ambiguity and integration cost.
UCI is a "living standard," evolving to meet mission needs while ensuring backward compatibility where possible—making it a future-proof foundation for mission-critical systems.
This repository includes all documents comprising the UCI Version 2.5. The heart of the standard is the UCI message schema located at UCI/OAC-STD-UCI_V2.5/UCI_MessageDefinitions_v2_5_0.xsd.
- Official Governance: Visit the Open Architecture Collaborative Working Group (OACWG) for updates and governance details. Contact via aflcmc.ase.architectures@us.af.mil.
- Related Standards: The UCI standard is leveraged by a variety of open architectures including Open Mission Systems (OMS).