Sbom Generate

---
name: sbom-generate
description: 'Generate CycloneDX 1.7 and/or SPDX 2.3 SBOMs for the repo, optionally cosign-signed, optionally cross-validated against syft output. Use when producing an SBOM for compliance, attaching to a release artefact, integrating with an SBOM registry, or satisfying a customer attestation request.'
license: Apache-2.0
allowed-tools: Bash(vulnetix:*) Read Grep Glob Write Bash(syft:*) Bash(cosign:*)
argument-hint: "[--format cyclonedx|spdx|both] [--sign] [--output PATH]"
user-invocable: true
model: sonnet
metadata:
  outputBudget: short
  cooldown: per-session
  chain: "vex-publish"
---
# Vulnetix SBOM Generate Skill

## Use when

- Producing an SBOM for SOC 2 / supply-chain compliance.
- Attaching an SBOM to a release artefact (GitHub release, container registry).
- Submitting to an SBOM registry (e.g. NTIA, in-house).
- Cosign signing for keyless OIDC supply-chain attestation.
- Cross-validating Vulnetix output against syft for component-count drift.

## Don't use for

- Just the license list — use `license-check`.
- Full compliance bundle (SBOM + VEX + SARIF) — use the `compliance-bundler` agent.
- Container-image SBOM — use `container-scan` with syft composition.

## Conventions

Follows `skills/_lib/contract.md`. In short: use the `vulnetix_*` MCP tools when the agent has them and the CLI otherwise — both shape their own output, so there is no jq step any more. Independent calls go out as concurrent Bash tool calls in one message. One trailing suggestion, not a playbook. See the contract for surface selection, output style and memory writes.

## Step 1: Load capabilities

Read `.vulnetix/capabilities.yaml`. Use `binaries.cosign` to gate signing. If user asks for `--sign` without cosign, surface install hint and skip signing.

## Step 2: Generate

```bash
OUT="${OUTPUT_DIR:-.vulnetix/sboms/$(date -u +%Y%m%dT%H%M%SZ)}"
mkdir -p "$OUT"

if [[ "$FORMAT" == "cyclonedx" ]] || [[ "$FORMAT" == "both" ]]; then
    vulnetix scan -o json-cyclonedx > "$OUT/sbom.cdx.json"
fi

if [[ "$FORMAT" == "spdx" ]] || [[ "$FORMAT" == "both" ]]; then
    vulnetix license -o json-spdx > "$OUT/sbom.spdx.json"
fi
```

## Step 3: Optional sign

```bash
[[ "$SIGN" == "true" ]] && cosign sign-blob --yes "$OUT/sbom.cdx.json" --bundle "$OUT/sbom.cdx.json.sig.bundle"
```

## Step 4: Compose with detected SBOM tools (conditional)

If `binaries.syft: true`, also produce a syft SBOM for cross-validation:

```bash
syft "$(pwd)" -o cyclonedx-json > "$OUT/sbom.syft.cdx.json"
```

Surface the diff (component count delta) so the user can spot gaps.

## Step 5: Render

```
SBOM(s) generated:
- CycloneDX: <path>  (<N components>, <M deps>)
- SPDX: <path>
- Signature: <path|none>
- Cross-validated with: syft (delta: +3 components)
```

Suggest the `compliance-bundler` agent for a full compliance bundle, or `vex-publish` to attach VEX.

## Edge cases & gotchas

- `vulnetix scan -o json-cyclonedx` produces CycloneDX 1.7; `vulnetix license -o json-spdx` produces SPDX 2.3. The flags are not interchangeable.
- Cosign signing requires keyless OIDC identity (Fulcio) or `--key file:cosign.key`. CI runners typically have OIDC; dev laptops may not.
- Cross-validation with syft requires `binaries.syft: true`. The delta = Vulnetix components - syft components; non-zero delta usually means private packages.
- CycloneDX 1.7 supports VEX-in-SBOM; pass `--include-vex` to embed the VEX block (otherwise it is a separate file).
- Output directory `.vulnetix/sboms/<ISO8601>/` is created on every invocation; never overwrites.
- For repos with no manifest files, the SBOM contains only the application metadata (no components). Check `components.length` before publishing.