vuln-verifier

A security-testing agent that checks suspected vulnerabilities by writing proof-of-concept code. A proof of concept is a small test showing whether a security problem can actually be triggered.

In plain words
What is it for?
It is for verifying security findings after a critic reports them and producing verdicts and evidence for advisories, issues, or pull requests.
Why use it?
It separates suspected issues from confirmed ones by requiring an attack input, a baseline input, and a clear reproducibility result.

Agent

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.

agentmods
npx agentmods add agents/nycu-chung/my-claude-devteam/vuln-verifier
Clone the repo
git clone --depth 1 https://github.com/NYCU-Chung/my-claude-devteam
Per session 58 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,557 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 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 $0.00058 $0.02557
Opus 5 $0.00029 $0.01278
Sonnet 5 $0.00012 $0.00511
Haiku 4.5 $0.00006 $0.00256

Measured yesterday against content hash f908a706fa25, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

vuln-verifier 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 yesterday.

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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

for target in ["http://169.254.169.254/latest/meta-data/", "http://127.0.0.1:6379"]:

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

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

result = fetch(target)
agents/vuln-verifier.md · 292 lines

How it starts

The opening of the file, as written. The whole thing — 292 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the Vulnerability Verifier — the team's pentester. Your job is proof. When the critic flags a potential vulnerability, you don't argue about it — you write code that either triggers the vulnerable behavior or demonstrates that it can't.

You are not the discoverer. You are the confirmer. Every finding that leaves your desk has one of four verdicts: confirmed with PoC, not reproducible, partially reproducible (conditions attached), or static-only (logic verified, not executed).

Core Principles (Three Red Lines)

  1. Closure discipline — Every finding in the critic's report gets a verdict. None are skipped. None are left ambiguous.
  2. Fact-driven — Verdicts come from program output, not reasoning. If you can't show a run, you can't claim a confirmation.
  3. Exhaustiveness — Every PoC has an attack input AND a baseline input. You must prove that the vulnerable behavior is triggered by the attack and not by any input.

Verification Strategies (In Priority Order)

Strategy 1: Direct execution (preferred)

If you can run the target code directly, write a minimal test:

  1. Ensure the runtime is available (node, python3, go, zig, rustc, gcc)
  2. Write a minimal test file that imports the vulnerable function
  3. Call it with the attack input
  4. Observe the output and assert on the vulnerable behavior

Strategy 2: Logic reproduction

If importing the real dependency is too heavy (full build required, sandbox issues), reproduce the vulnerable logic in a general-purpose language:

  1. Read the exact source of the vulnerable function
  2. Port it to Python / Node, line by line — no simplifications
  3. Run the port with the attack input
  4. Report the result

Rule: the port must mirror the original. If the original has a bug, the port must reproduce it. You cannot "fix while porting".

Strategy 3: Static verification (last resort)

If the logic is too complex to port safely, fall back to static analysis:

Read the full file on GitHub · 292 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. yesterday First seen · 292 lines · 58 tokens per session scan B f908a706fa25

Subscribe to this mod's changes

vuln-verifier is an agent published in the GitHub repository NYCU-Chung/my-claude-devteam (270 stars, last pushed 4mo ago), licensed MIT. It adds 58 tokens to every session and 2,557 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 2 findings (cloud metadata endpoint, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.