sigma-rule-reviewer

sigma-rule-reviewer is a skill for Claude Code from WRG-11/wrg-sigma-rules. It costs 25 tokens per session (158 once invoked), scanned A, original, MIT.

A reviewer for Sigma rules, which are portable YAML descriptions of security detections. It checks an existing rule for format compliance, detection quality, and unnecessary alerts.

In plain words
What is it for?
Use it to validate and improve a pasted or stored Sigma rule, review noisy detections, and suggest safer revisions.
Why use it?
It helps catch rules that cannot load, miss important attacks, or generate too many false alarms before they are used in security monitoring.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the wrg-sigma-rules plugin — 3 skills, 1 MCP server shipped together

Good fit Use it to validate and improve a pasted or stored Sigma rule, review noisy detections, and suggest safer revisions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer
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 WRG-11/wrg-sigma-rules --skill sigma-rule-reviewer
Clone the repo
git clone --depth 1 https://github.com/WRG-11/wrg-sigma-rules

Made for: Claude Code.

Or install wrg-sigma-rules, the plugin that ships this one along with the rest of its 3 skills, 1 MCP server.

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 sigma-rule-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer/github.svg)](https://agentmods.dev/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer)
Your own site
<a href="https://agentmods.dev/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer"><img src="https://agentmods.dev/badge/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer/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 sigma-rule-reviewer

Your own site · 80×15
<a href="https://agentmods.dev/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer"><img src="https://agentmods.dev/badge/skills/wrg-11/wrg-sigma-rules/sigma-rule-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 158 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00025 $0.00158
Opus 5 $0.00013 $0.00079
Sonnet 5 $0.00005 $0.00032
Haiku 4.5 $0.00003 $0.00016

Measured yesterday against content hash ac19f3c2a426, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

sigma-rule-reviewer 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 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.

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.

plugins/wrg-sigma-rules/skills/sigma-rule-reviewer/SKILL.md · 17 lines

What it actually says

Sigma Rule Reviewer

Read the supplied YAML or requested file, then call the wrg-sigma-rules MCP server's validate_rule. Report parse errors separately from quality warnings. Explain what the detection actually selects, its required telemetry, and one realistic benign trigger. Do not silently rewrite the rule; show a small diff and revalidate only if the user requests changes.

Treat falsepositives placeholders and leftover REPLACE_ME markers as actionable findings. A correlation rule failing for a Lucene-family backend is a backend capability limitation, not proof that the Sigma rule is invalid.

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 Changed · -143 lines · -58 tokens per session ac19f3c2a426
  2. 12d ago First seen · 160 lines · 83 tokens per session scan A 021770956405

Subscribe to this mod's changes

sigma-rule-reviewer is a skill published in the GitHub repository WRG-11/wrg-sigma-rules (2 stars, last pushed yesterday), licensed MIT. It adds 25 tokens to every session and 158 once invoked, about $0.0001 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 2026-08-31.

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