REF-070: OCI Image Specification

REF-070: OCI Image Specification

Citation

Open Container Initiative. (2026). OCI Image Specification. OCI. https://github.com/opencontainers/image-spec

Descriptor specification: https://github.com/opencontainers/image-spec/blob/main/descriptor.md

Document Profile

AttributeValue
Year2017-2026
TypeContent and descriptor specification
StatusActive OCI standard
GRADE / QualityA - normative content descriptor specification with broad adoption
AIWG RelevanceMedium - Descriptor and digest model for verifiable resource bundles

Executive Summary

The OCI Image Specification defines content descriptors that bind media type, size, and digest. The digest acts as a content identifier: clients can fetch bytes from an untrusted or intermediate source and independently verify that the bytes match the expected descriptor.

AIWG uses the same pattern for web resources: manifests commit descriptor paths, sizes, and SHA-256 digests; cache reads re-check the descriptor before the CLI uses a resource body.

AIWG Implementation Mapping

OCI Image ConceptAIWG Resource Implication
Descriptor digestManifest `sha256` fields for bundles, prebuilt indices, and raw resources
Descriptor sizeManifest byte-size commitments for cache and body validation
Image manifestAIWG release manifest
Image indexFuture multi-graph or multi-platform resource manifest extensions
Content addressabilityCache key includes version and manifest digest

Design Implications

  • Descriptor verification should remain mandatory before any resource body is

parsed or rendered.

  • Cache cleanup must preserve digest-keyed generations that are pinned by a

project lockfile.

  • Descriptor metadata should be treated as public compatibility surface because

downstream tooling can build reproducibility checks on it.

Cross-References

  • REF-069: OCI Distribution Specification defines the registry API around OCI

manifests and blobs.

  • REF-071: SRI is a simpler content-hash precedent for web fetches.
  • `src/resources/web-release.ts`: AIWG descriptor verification implementation.