Generate Slsa

Generate SLSA

Add a SLSA Generation step to an existing Harness pipeline to generate SLSA provenance and optionally attest/sign the .att file in the container registry. Pipeline YAML uses type: provenance (UI label: SLSA Generation; do not use SlsaGeneration — API rejects it).

This skill only works with existing pipelines — do not create standalone SLSA-only pipelines.

Prerequisites: Image must be built and pushed (or available in registry) before SLSA runs. Key-based attestation requires Cosign key pair secrets (/create-secret). Harness Cloud builds enable SLSA Level 3 provenance when using hosted infrastructure.

Guide the user through a step-by-step interactive wizard (same UX as /configure-repo-scan):

• Wizard: references/interactive-wizard-flow.md
• UI ↔ YAML: references/slsa-generation-step.md
• CD containerized step groups: references/cd-containerized-step-group.md

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Interaction model (mandatory)

1. One question per turn — use AskQuestion when available; otherwise numbered options with (Recommended).
2. Opening message — add SLSA Generation after image build/push; mention attestation options.
3. Progress breadcrumb — after pipeline fetch:

Pipeline · Placement · Source · Details · Attestation · Submit

1. Record answers — running summary; do not re-ask unless the user changes direction.
2. Fetch before configure — harness_get before placement/source questions.
3. Show pipeline structure — highlight build/push steps and existing provenance / SscaOrchestration steps (UI: SLSA Generation).
4. Infer connector from build/push — skip connector question when unambiguous from YAML.
5. Never guess image tags — always ask for image/repo in Phase 7.
6. Confirm before write — summary + harness_update only after user confirms.
7. Stop after update — after successful harness_update, provide a configuration summary and

point the user to /run-pipeline to execute. Do not call harness_execute, poll executions, or run harness_diagnose in this skill (same pattern as /configure-repo-scan).

1. Phase 3 Placement is mandatory — always run Phase 2 then Phase 3, even with one CI stage or prior session context.
2. Sequential with SBOM — if SscaOrchestration exists, place SLSA after it; never parallel (Cosign race).
3. CD path — Deploy stage steps go inside containerized stepGroup only — see CD reference.

Full phase prompts: references/interactive-wizard-flow.md.

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Instructions

Wizard phases

| Phase | Breadcrumb | Action | |-------|------------|--------| | 0 | Pipeline | AskQuestion: pipeline URL ready? | | 1 | Pipeline | Collect URL → harness_get | | 2 | Pipeline | Display structure; note build/push + SBOM steps | | 3 | Placement | Mandatory AskQuestion: stage + position (after build/push recommended) | | 3b | Placement (CD) | Service, env, infra, step group if new Deploy stage | | 4 | Source | AskQuestion: Third-Party, HAR, or Local | | 5 | Source | AskQuestion: registry provider (Third-Party only) | | 6 | Details | Connector (skip if obvious) | | 7 | Details | Image/repo; optional digest expression | | 8 | Attestation | AskQuestion: keyless, keybased, vault, or none | | 9 | Submit | AskQuestion: confirm pipeline update |

After Phase 9 confirm → generate YAML, insert step, harness_update, then provide summary (do not run the pipeline).

Supported stage types

| Stage type | Placement notes | |------------|-----------------| | CI | Recommended — immediately after BuildAndPush* or image push Run step | | Deployment | Containerized step group only; before deploy — uncommon for generation | | Security | End of stage when scanning pre-built registry images |

After the wizard — backend steps

Extract connectors from pipeline YAML

From BuildAndPushDockerRegistry, BuildAndPushECR, Run, Plugin, SscaOrchestration, provenance (SLSA Generation), or SscaArtifactSigning steps — reuse connectorRef / connector.

Generate SLSA step YAML

Use only wizard answers. Default attestation: keyless Harness OIDC when user chose defaults.

Docker Registry — matches reference UI (key-based attestation):

- step:
    identifier: slsageneration
    name: slsa-generation
    type: provenance
    spec:
      source:
        type: docker
        spec:
          connector: lavakush07
          repo: lavakush07/easy-buggy-app:blog
      attestation:
        type: keybased
        spec:
          privateKey: account.cosign_private_key
          password: account.cosign_password
    timeout: 15m

Keyless attestation (default for “use defaults”):

      attestation:
        type: keyless
        spec:
          oidcProvider: harness

With digest from Build and Push:

      source:
        type: docker
        spec:
          connector: 
          repo: /:
          digest: .spec.execution.steps..output.outputVariables.digest>

Amazon ECR:

      source:
        type: ecr
        spec:
          connector: 
          image: 
          region: 
          account: 

Google GCR / GAR / Azure ACR / HAR / Local: see references/slsa-generation-step.md.

No attestation: omit attestation block.

Insert step into pipeline YAML

• Insert at Phase 3 placement — after build/push (or after generate_sbom when both exist).
• Do not modify unrelated steps, variables, or failure strategies.
• Step identifier: slsageneration (suffix _cd in CD when CI already has one).
• CD: inside containerized stepGroup.steps only.

Update pipeline via MCP

harness_update
  resource_type: pipeline
  resource_id: 
  org_id: 
  project_id: 
  body: { yamlPipeline: "" }

On validation errors, read the API message, fix fields (often repo vs image, attestation spec), retry.

Provide summary

Report the results to the user (same pattern as /configure-repo-scan — do not execute the pipeline):

## SLSA Generation Configured

**Pipeline:** 
**Step:** SLSA Generation (`provenance`)
**Location:** Stage "", 
**Source:** docker —  — 
**Attestation:** Key-based (account.cosign_private_key) — or as configured

**Pipeline URL:** https://app.harness.io/ng/account//module/ci/orgs//projects//pipelines//pipeline-studio/

**Note:** Review the SLSA Generation step in Pipeline Studio to adjust Advanced settings.

**Provenance:** After a successful run, view on the Supply Chain tab and in SCS Artifacts.

### Next Steps
1. Run the pipeline via `/run-pipeline` to verify the SLSA Generation step executes successfully
2. If the run fails, diagnose with `/debug-pipeline`
3. Add SLSA verification with `/enforce-slsa`
4. Pair with `SscaOrchestration` (Generate SBOM) — run SBOM then SLSA sequentially
5. Automate with `/create-trigger`

CD pipelines: note in the summary if runtime inputs (service artifact, environment, infrastructure) will be required at run time — the user provides those via /run-pipeline or Harness UI Run.

---

Examples

After Docker build/push — key-based attestation (reference UI)

/generate-slsa
Add SLSA Generation to my CI pipeline after docker push — lavakush07/easy-buggy-app:blog, key-based attest with account cosign secrets

Keyless defaults on Harness Cloud

/generate-slsa
Use defaults — keyless Harness OIDC after Build_and_Push step

With digest expression

/generate-slsa
Generate SLSA for image from Build_and_Push digest output — keyless attest

Placement must be explicit

/generate-slsa
add slsa to the pipeline

Agent must still run Phase 2 + Phase 3 — do not assume stage or skip placement.

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Performance Notes

• Only existing pipelines — do not create standalone SLSA pipelines (may append Deploy stage for CD).
• Wizard UX is mandatory — one question per turn; see references/interactive-wizard-flow.md.
• Placement after build/push — SLSA needs a published image (tag or digest).
• Sequential with SBOM — never parallel SBOM + SLSA attestation (Cosign registry race).
• YAML step type is provenance — not SlsaGeneration (API enum rejects SlsaGeneration).
• Docker UI Image field → YAML source.spec.repo (not image; SBOM SscaOrchestration uses image for docker).
• Key-based attestation — private key + password must be Harness file secrets (/create-secret).
• CD generation is rare — prefer CI generation + CD /enforce-slsa; see CD reference.
• Do not execute pipelines in this skill — use /run-pipeline after configuration (same as /configure-repo-scan).
• Do not use for dashboard-only SSCA config — use /manage-supply-chain instead.

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Troubleshooting

Pipeline Not Found

• Verify org/project; harness_list (resource_type: pipeline).

Connector Not Found

• Search build/push steps for connectorRef; harness_search for Docker registry connectors.

Image Not Found / Invalid Reference

• Use single repo string — e.g. lavakush07/easy-buggy-app:blog.
• Symptom: provenance generation fails — confirm image exists at run time.

Attestation Failed (Key-based)

• Verify file secrets exist and Cosign key is ecdsa-p256.
• Password secret must match the key pair generation password.
• JFrog registries need extra connector permissions for .att upload.

Attestation Failed (Keyless)

• Requires Harness CI execution context; configure Connector for Keyless Signing for non-harness OIDC.

SBOM + SLSA Race

• Symptom: only one .att in registry — steps ran in parallel.
• Fix: reorder — SBOM then SLSA sequentially in the same stage.

CD Validation Errors

• provenance (SLSA Generation) in Deploy stages must be inside stepGroup with stepGroupInfra.
• See references/cd-containerized-step-group.md.

YAML Rejects SlsaGeneration Step Type

• Symptom: does not have a value in the enumeration for SlsaGeneration.
• Fix: use type: provenance — validate with harness_schema(resource_type="pipeline", path="steps").

Skipped Placement

• Re-run wizard from Phase 2; ask stage + position explicitly.

Pipeline Run Failed

• Use /run-pipeline to execute and /debug-pipeline to diagnose failures
• Verify image exists in registry and Cosign secrets are valid file secrets
• CD: provide service/env/infra inputs via /run-pipeline or Harness UI Run — do not guess runtime inputs

MCP Errors

• CONNECTOR_NOT_FOUND — verify connector identifier.
• ACCESS_DENIED — PAT needs pipeline edit permission.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: harness
• Source: harness/harness-skills
• License: Apache-2.0
• Homepage: https://developer.harness.io/docs/platform/harness-ai/harness-skills/

Install and usage instructions live in the source repository linked above.