Bundle format

The switchboard.descriptor/v1 descriptor, the identity zone, and the on-registry object layout.

A bundle is a directory of artifacts described by a descriptor.json with schema switchboard.descriptor/v1.

descriptor.json

{
  "schema": "switchboard.descriptor/v1",
  "abi": "switchboard/v3",
  "manifest": {
    "name": "my-rules",
    "abi": "switchboard/v3",
    "entrypoint": "handle",
    "language": "go-tinygo"
  },
  "artifacts": {
    "module.wasm": { "digest": "sha256:…", "size": 30762 },
    "tests.yaml": { "digest": "sha256:…", "size": 372 }
  },
  "provenance": {
    "built_at": "2026-07-16T14:02:58Z",
    "builder": "switchboard/0.1.0 tinygo/0.41.1",
    "source_commit": "9f31c2e…"
  },
  "signatures": []
}

Field	In identity	Description
`schema`	yes	Descriptor schema version.
`abi`	yes	Host-function ABI the module targets (`switchboard/v3`).
`manifest`	yes	Bundle name, ABI, entrypoint export, source language.
`artifacts`	yes	Digest and size of every artifact in the bundle.
`provenance`	no	Build time, builder version, source commit. Annotation only.
`signatures`	no	Reserved for future bundle signing (Ed25519/Sigstore planned).

Bundle identity

The bundle ID is sha256-<hex> computed over the canonical JSON of the identity zone: schema, abi, manifest, and artifacts.

Because provenance and signatures sit outside the identity zone:

Byte-identical rebuilds produce the same ID, so re-deploying unchanged content skips the upload entirely.
Signing or annotating a bundle later never changes what it is.

Every registry verifies, on both upload and download, that each artifact matches its declared digest and that the stored bundle ID matches the descriptor-derived ID. Corruption and tampering fail closed, before activation.

On-registry layout

channels/prod.json
revisions/prod/0000000041.json
revisions/prod/0000000042.json
bundles/sha256-<digest>/module.wasm
bundles/sha256-<digest>/manifest.json
bundles/sha256-<digest>/tests.yaml
bundles/sha256-<digest>/checksum.txt
bundles/sha256-<digest>/descriptor.json

With a namespace, everything nests under namespaces/<name>/….

Compatibility

checksum.txt (a module-only digest) is still written and verified for compatibility, but descriptor.json is authoritative.
Legacy bundles without a descriptor still load, with a warning.
Proxies refuse bundles whose abi they don’t support.