verifying-build-provenance-with-slsa-sigstore

verifying-build-provenance-with-slsa-sigstore is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 55 tokens per session (2,526 once invoked), scanned A, original, MIT.

A security check for proving where a software artifact came from and whether it was changed after it was built. It uses SLSA provenance and Sigstore tools such as cosign and slsa-verifier.

In plain words
What is it for?
Use it in software supply-chain checks to verify signatures, attestations, trusted GitHub Actions identities, and SLSA build levels.
Why use it?
A compiled release can look legitimate even if a build system was compromised or the file was replaced. Verification provides evidence about the source, builder, identity, and integrity of the artifact.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it in software supply-chain checks to verify signatures, attestations, trusted GitHub Actions identities, and SLSA build levels.

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Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add adriannoes/awesome-agentic-ai --skill verifying-build-provenance-with-slsa-sigstore
Clone the repo
git clone --depth 1 https://github.com/adriannoes/awesome-agentic-ai

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for verifying-build-provenance-with-slsa-sigstore

README.md
[![agentmods](https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore/github.svg)](https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore)
Your own site
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for verifying-build-provenance-with-slsa-sigstore

Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/verifying-build-provenance-with-slsa-sigstore.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,526 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00055 $0.02526
Opus 5 $0.00028 $0.01263
Sonnet 5 $0.00011 $0.00505
Haiku 4.5 $0.00006 $0.00253

Measured 9d ago against content hash f2f8c711b285, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

verifying-build-provenance-with-slsa-sigstore scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -sSL https://github.com/slsa-framework/slsa-verifier/releases/latest/download/slsa-verifier-linux-amd64 \
cursor-claude-codex/skills/anthropic-cybersecurity-skills/skills/verifying-build-provenance-with-slsa-sigstore/SKILL.md · 192 lines

How it starts

The opening of the file, as written. The whole thing — 192 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verifying Build Provenance with SLSA and Sigstore

Overview

Build-provenance verification answers a question that defeats many supply-chain attacks: was this artifact actually built from the source I think it was, by the builder I trust, without tampering? Attackers who compromise a build system, swap a compiled release, or inject a malicious step (as in the SolarWinds and 3CX incidents) produce artifacts that look legitimate but lack verifiable provenance. SLSA (Supply-chain Levels for Software Artifacts, https://slsa.dev) defines Build levels (L1–L3) describing increasing provenance integrity, and Sigstore (https://www.sigstore.dev) provides the signing and transparency infrastructure: cosign for signing/verifying artifacts and attestations, Fulcio for short-lived keyless certificates bound to an OIDC identity, and Rekor as a tamper-evident transparency log.

This skill covers verifying signatures and SLSA provenance with cosign (cosign verify, cosign verify-attestation, cosign verify-blob-attestation) and slsa-verifier (slsa-verifier verify-artifact), enforcing the builder identity (the GitHub Actions workflow that produced the artifact) and the expected source repository. Keyless verification ties trust to an OIDC issuer (e.g., https://token.actions.githubusercontent.com) and a certificate identity rather than a long-lived private key.

This maps to MITRE ATT&CK T1195 — Supply Chain Compromise (provenance verification detects/blocks tampered artifacts) and NIST CSF PR.DS-06 (integrity-checking mechanisms are used to verify software, firmware, and information integrity).

When to Use

  • In CI/CD before deploying or promoting any container image or release binary.
  • When consuming third-party artifacts (base images, Go/npm releases) that publish attestations.
  • When establishing a SLSA Build L3 producer pipeline and enforcing it at the consumer side.
  • During incident response to confirm whether a deployed artifact's provenance is intact.
  • In admission control (e.g., Kubernetes via policy-controller / Kyverno) to admit only verified images.

Read the full file on GitHub · 192 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 192 lines · 55 tokens per session scan A f2f8c711b285

Subscribe to this mod's changes

verifying-build-provenance-with-slsa-sigstore is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 14d ago), licensed MIT. It adds 55 tokens to every session and 2,526 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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