soundcheck: Skill for Claude Code

.claude/skills/llm-supply-chain/SKILL.md

llm-supply-chain is a skill for Claude Code from thejefflarson/soundcheck. It costs 71 tokens per session (694 once invoked), scanned A, original, MIT.

A security check for AI models downloaded from outside sources or loaded through third-party services. It looks for tampered model files, changeable version names, and unreviewed model sources.

In plain words
What is it for?
Use it when code downloads or loads pre-trained models, connects to external AI model providers, or chooses model versions.
Why use it?
A compromised model can contain a hidden backdoor that remains in use even after later training or updates.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is thejefflarson/soundcheck's own configuration. It tells Claude Code how to work on soundcheck itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything soundcheck configures →

Part of the soundcheck plugin — 52 skills, 7 agents, 2 hooks shipped together

Reuse

Borrowing it

Nothing to install: this file belongs to thejefflarson/soundcheck. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/thejefflarson/soundcheck/main/.claude/skills/llm-supply-chain/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/thejefflarson/soundcheck

Made for: Claude Code.

Or install soundcheck, the plugin that ships this one along with the rest of its 52 skills, 7 agents, 2 hooks.

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 llm-supply-chain

README.md
[![agentmods](https://agentmods.dev/badge/skills/thejefflarson/soundcheck/llm-supply-chain.svg)](https://agentmods.dev/skills/thejefflarson/soundcheck/llm-supply-chain)
Your own site
<a href="https://agentmods.dev/skills/thejefflarson/soundcheck/llm-supply-chain"><img src="https://agentmods.dev/badge/skills/thejefflarson/soundcheck/llm-supply-chain.svg" alt="Measured on agentmods" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 694 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00071 $0.00694
Opus 5 $0.00036 $0.00347
Sonnet 5 $0.00014 $0.00139
Haiku 4.5 $0.00007 $0.00069

Measured 6d ago against content hash e91af7f6bd9c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

llm-supply-chain scanned grade A with 0 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 6d ago.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/llm-supply-chain/SKILL.md · 64 lines

How it starts

The opening of the file, as written. The whole thing — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.

LLM Supply Chain Security Check (OWASP LLM05:2025)

What this checks

Protects against compromised or backdoored models introduced through unverified downloads, floating version tags, or unreviewed third-party providers. A tampered model weight file or a silently swapped latest tag can introduce persistent backdoors that survive retraining.

Vulnerable patterns

  • Model artifact downloaded from an arbitrary host or URL with no checksum or signature verification
  • Model identifier that uses a floating tag (latest, main, a mutable branch) instead of an exact pinned revision
  • Third-party model integrated with no review of model card, license, or provenance
  • Automated model-update job in CI that bumps revisions without a human approval gate

Fix immediately

Flag the vulnerable code and explain the risk. Then suggest a fix that establishes these properties:

  1. Model revisions are pinned to an exact commit SHA or content digest, never a mutable name like main or latest. A floating tag lets the registry (or a registry compromise) silently swap what you load on the next pull — including backdoored weights that look identical by name.
  2. Weight files are checksum-verified after download. A cryptographic digest (SHA-256 or stronger) of the expected bytes is pinned in version control; the loader computes the digest on the downloaded file and refuses to use it on mismatch. Pinning the revision alone does not help if the artifact is served from a compromised CDN.
  3. Model source is validated against an allowlist of approved organizations or registries before download begins. A wildcard organization field is the supply-chain equivalent of accepting any author.
  4. Automated model updates have a human approval gate. A CI job that bumps a pinned revision without review is a backdoor delivery channel; rotate revisions through PRs with signed artifacts reviewed by a human.

Translate these principles to the loader API, registry client, and CI system of the audited file. Use the SDK's documented pinning and verification mechanisms — do not implement ad-hoc checks.

Read the full file on GitHub · 64 lines

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. 6d ago First seen · 64 lines · 71 tokens per session scan A e91af7f6bd9c

Subscribe to this mod's changes

llm-supply-chain is a skill published in the GitHub repository thejefflarson/soundcheck (20 stars, last pushed 1mo ago), licensed MIT. It adds 71 tokens to every session and 694 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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