`slsa` attestor

Emits a SLSA Provenance v1.0 predicate assembled from sibling attestors that ran in the same collection.

Name	`slsa`
Predicate type	`https://slsa.dev/provenance/v1.0`
Lifecycle	`postproduct`
Default binary?	No
Recommended trace	off — no syscall tracing needed
Auto-attaches when	Not auto-detected — attach explicitly with `-a`.

The facts in this box are generated from the cilock binary's own catalog (cilock tools list). Do not hand-edit — run npm run gen:catalog.

What it captures

The predicate is the prov.Provenance struct from attestation/intoto/provenance, which mirrors the SLSA v1.0 spec:

buildDefinition.buildType — set to the constant https://aflock.ai/[email protected].
buildDefinition.externalParameters — { "command": "<joined command-run argv>" } (populated from the command-run sibling).
buildDefinition.internalParameters — { "env": { ... } } (populated from the environment sibling).
buildDefinition.resolvedDependencies — array of ResourceDescriptor{name,digest} entries built from git remotes + commit digest, the GitHub/GitLab JWT sha claim, and every material attestor entry.
runDetails.builder.id — see "Builder identity" below.
runDetails.builder.version, runDetails.builder.builderDependencies — present in the schema but not populated.
runDetails.metadata.invocationId — pipeline URL (GitHub/GitLab/Jenkins) or AWS CodeBuild build ARN.
runDetails.metadata.startedOn / finishedOn — timestamps copied from the command-run attestor's span.
runDetails.byproducts — present in the schema but not populated.

Subjects come from the product attestor (as file:<name>) and from any oci attestor subjects (image references), merged together.

When to use

Use whenever your verification chain expects upstream SLSA Provenance v1 consumers — cosign verify-attestation --type slsaprovenance1, slsa-verifier, OpenSSF Scorecard, or any policy engine that keys off the https://slsa.dev/provenance/v1.0 predicate URI. The slsa attestor is the canonical bridge between cilock's collection-style attestations and the SLSA ecosystem.

Flags

Flag	Type	Default	Description
`--attestor-slsa-export`	bool	`false`	Emit the SLSA predicate as its own standalone DSSE envelope (in addition to being embedded in the collection).

Output shape

{
  "buildDefinition": {
    "buildType": "https://aflock.ai/[email protected]",
    "externalParameters": { "command": "go build ./..." },
    "internalParameters": { "env": { "PATH": "...", "HOME": "..." } },
    "resolvedDependencies": [
      { "name": "origin", "digest": { "sha1": "abc123..." } },
      { "digest": { "sha1": "def456..." } }
    ]
  },
  "runDetails": {
    "builder": { "id": "https://aflock.ai/[email protected]" },
    "metadata": {
      "invocationId": "https://github.com/owner/repo/actions/runs/123",
      "startedOn": "2026-05-21T12:00:00Z",
      "finishedOn": "2026-05-21T12:00:05Z"
    }
  }
}

Gotchas

Builder identity is auto-selected from sibling attestors. Defaults to https://aflock.ai/[email protected]; promoted to [email protected], [email protected], [email protected], or [email protected] if the matching sibling ran. If the builder stays at the default, the attestor logs a warning suggesting you add a build-system attestor.
Sibling-attestor dependencies: with no git, material, command-run, environment, product, or oci in the same step, the predicate is essentially empty — the slsa attestor only assembles, it does not collect.
Wrapped vs exported: without --attestor-slsa-export, the predicate ships inside the cilock collection envelope. Upstream SLSA tooling expects a top-level DSSE with the https://slsa.dev/provenance/v1.0 predicate type — turn the flag on for those consumers.
Two registrations exist: the active slsa attestor (postproduct, type .../v1.0) and a slsa-provenance-v1 verify-only factory (type .../v1) used by the external-attestation flow. Only the former runs during a build.
The slsa attestor implements Subjecter and merges product subjects with OCI subjects, so container image digests are not silently dropped.

CLI example

Real SLSA Provenance v1.0 emitted from command-run + material + product.

cilock run --step slsa-provenance \
  --signer-file-key-path key.pem --outfile attestation.json --workingdir . \
  --attestations slsa \
  -- make build 

Validated against a real build emitting SLSA v1.0 provenance. See the full real-data example at https://github.com/aflock-ai/attestor-compliance-examples/tree/main/38-slsa.

What it captures​

When to use​

Flags​

Output shape​

Gotchas​

CLI example​

See also​