implementing-sigstore-for-software-signing

implementing-sigstore-for-software-signing is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 107 tokens per session (2,974 once invoked), scanned B, original, MIT.

A software-signing setup based on Sigstore, which links an artifact to the identity that signed it and records the event in a public transparency log. It uses Cosign, Fulcio certificates, and Rekor to sign and verify container images, binaries, and other build outputs.

In plain words
What is it for?
Use it to sign CI/CD build artifacts, inspect their signing history, verify images from registries, and enforce signed-image rules in Kubernetes.
Why use it?
It lets teams verify where software came from without maintaining long-lived signing keys. Verification can prevent unsigned or unauthorized images from being accepted for deployment.

Skill for Claude CodeCodex

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

Good fit Use it to sign CI/CD build artifacts, inspect their signing history, verify images from registries, and enforce signed-image rules in Kubernetes.

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Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing
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 implementing-sigstore-for-software-signing
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 implementing-sigstore-for-software-signing

README.md
[![agentmods](https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing/github.svg)](https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing)
Your own site
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing/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 implementing-sigstore-for-software-signing

Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/implementing-sigstore-for-software-signing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 107 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,974 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Tool Misuse · line 93
    Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
    Fix: Limit tool chaining depth and validate the output of each tool before passing it to the next. Require explicit user approval for multi-step chains.
  • medium Privilege Escalation · line 93
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
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 $0.00107 $0.02974
Opus 5 $0.00053 $0.01487
Sonnet 5 $0.00021 $0.00595
Haiku 4.5 $0.00011 $0.00297

Measured 9d ago against content hash 4f1db3501f44, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

implementing-sigstore-for-software-signing scanned grade B with 2 findings 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- **Install from binary release**: Download the appropriate binary from the Cosign GitHub releases page and verify its checksum. On Linux: `curl -LO https://github.com/sigstore/cosign/releases/latest/download/cosign-linu

Makes network callslowCapability

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

- **Install from binary release**: Download the appropriate binary from the Cosign GitHub releases page and verify its checksum. On Linux: `curl -LO https://github.com/sigstore/cosign/releases/latest/download/cosign-linu
cursor-claude-codex/skills/anthropic-cybersecurity-skills/skills/implementing-sigstore-for-software-signing/SKILL.md · 204 lines

How it starts

The opening of the file, as written. The whole thing — 204 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Implementing Sigstore for Software Signing

When to Use

  • Signing container images and software artifacts without managing long-lived cryptographic keys
  • Establishing verifiable provenance for build outputs in CI/CD pipelines using OIDC identity binding
  • Querying the Rekor transparency log to audit when and by whom an artifact was signed
  • Verifying that container images pulled from registries were signed by authorized identities and issuers
  • Integrating Sigstore verification into Kubernetes admission controllers to enforce signed-image policies

Do not use for signing artifacts that require air-gapped or offline signing workflows where OIDC authentication is unavailable, for environments that cannot reach the public Sigstore infrastructure (Fulcio, Rekor) and have no private instance deployed, or as a replacement for traditional PGP/GPG signing where regulatory compliance mandates specific key management procedures.

Prerequisites

  • Cosign CLI v2.4+ installed (go install github.com/sigstore/cosign/v2/cmd/cosign@latest or binary release)
  • Access to an OIDC identity provider supported by Fulcio (Google, GitHub, Microsoft, or a custom OIDC issuer)
  • Container registry credentials (for signing container images) with push access to store signature objects
  • Python 3.9+ with sigstore, requests, and cryptography packages for the automation agent
  • Network access to fulcio.sigstore.dev, rekor.sigstore.dev, and tuf-repo-cdn.sigstore.dev (or private Sigstore instance URLs)

Workflow

Step 1: Install and Configure Cosign

Install Cosign and verify it can reach the Sigstore infrastructure:

  • Install from binary release: Download the appropriate binary from the Cosign GitHub releases page and verify its checksum. On Linux: curl -LO https://github.com/sigstore/cosign/releases/latest/download/cosign-linux-amd64 && chmod +x cosign-linux-amd64 && sudo mv cosign-linux-amd64 /usr/local/bin/cosign
  • Verify installation: Run cosign version to confirm the version and check connectivity to Sigstore services with cosign initialize which fetches the TUF root of trust
  • Configure custom infrastructure (optional): If running a private Sigstore stack, set --fulcio-url, --rekor-url, and --oidc-issuer flags or use environment variables COSIGN_REKOR_URL and COSIGN_FULCIO_URL

Read the full file on GitHub · 204 lines

Files

What ships with it

3 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 · 204 lines · 107 tokens per session scan B 4f1db3501f44

Subscribe to this mod's changes

implementing-sigstore-for-software-signing is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 14d ago), licensed MIT. It adds 107 tokens to every session and 2,974 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it B with 2 findings (asks for root, 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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