UARC (Universal Application Runtime Contract)

Version: 1.0
Status: Active

Terminology & Scope

In this specification and related documents, the following terms are used with strict distinctions.

Term	Conceptual role	Analogy in HTTP/Web	Definition
UARC	Standard	HTTP	Universal Application Runtime Contract. The umbrella name of the specification that defines the protocol, interfaces, and the full verification flow.
Capsule	Format	HTML	The package format and manifest format defined by UARC. A portable container unit that is implementation-independent.
Capsuled	Implementation	Apache / Nginx	A reference runtime engine implementation compliant with UARC. An OSS daemon.

Note: "Capsule" refers strictly to the data format (e.g., .capsule file, capsule.capnp schema) defined in this repository. It should not be confused with "Ato" or other commercial products that utilize this format.

Overview

UARC is a specification for runtime-agnostic, verifiable application execution. The same Capsule contract can run on WebAssembly, OCI containers, or native processes—enabling portability across heterogeneous environments.

It defines:

• Contract Format: How applications declare their requirements (capsule.toml)
• Verification Layers: L1-L5 validation pipeline
• Identity & Networking: SPIFFE-based identity management
• Observability: Audit logging and metrics collection

Repository Structure

uarc/
├── SPEC.md           # UARC V1 Specification
├── schema/           # Cap'n Proto schema definitions
│   └── capsule.capnp # CapsuleManifest schema (SSOT)
├── proto/            # gRPC/Protobuf service definitions
│   ├── common/v1/    # Shared types (RunPlan, etc.)
│   └── engine/v1/    # Engine service (Deploy, Stop, etc.)
├── buf.yaml          # Buf module configuration
└── buf.gen.yaml      # Code generation configuration

Note: Coordinator API is Ato-specific and lives in ato-coordinator.

Code Generation

Prerequisites

• Buf CLI

Generate Go Code

buf generate --path proto/

Generated code will be placed in ../ato-coordinator/pkg/gen/proto/.

Rust (tonic-build)

Rust code is generated at build time via capsuled/build.rs.

Related Repositories

• capsuled - OSS Engine (Rust)
• capsule-cli - Developer CLI (Rust)
• ato-coordinator - SaaS Backend (Go)
• ato-desktop - Desktop App (Tauri)

License

Apache-2.0