cross-checker

cross-checker is a skill for Claude Code from a-ariff/ariff-claude-plugins. It costs 36 tokens per session (575 once invoked), scanned A, original, MIT.

A verification process that checks claims against independent evidence such as source code, tests, documentation, configuration, dependencies, and version history.

In plain words
What is it for?
Checking whether code behavior matches tests and documentation, investigating discrepancies, and confirming intended behavior before making changes.
Why use it?
It reduces the chance of acting on a claim that is supported by only one incomplete or outdated source.

Skill for Claude Code

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

Part of the cross-checker plugin — 1 skill shipped together

Good fit Checking whether code behavior matches tests and documentation, investigating discrepancies, and confirming intended behavior before making changes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/a-ariff/ariff-claude-plugins/cross-checker
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 a-ariff/ariff-claude-plugins --skill cross-checker
Clone the repo
git clone --depth 1 https://github.com/a-ariff/ariff-claude-plugins

Made for: Claude Code.

Or install cross-checker, the plugin that ships this one along with the rest of its 1 skill.

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 cross-checker

README.md
[![agentmods](https://agentmods.dev/badge/skills/a-ariff/ariff-claude-plugins/cross-checker.svg)](https://agentmods.dev/skills/a-ariff/ariff-claude-plugins/cross-checker)
Your own site
<a href="https://agentmods.dev/skills/a-ariff/ariff-claude-plugins/cross-checker"><img src="https://agentmods.dev/badge/skills/a-ariff/ariff-claude-plugins/cross-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 575 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 $0.00036 $0.00575
Opus 5 $0.00018 $0.00287
Sonnet 5 $0.00007 $0.00115
Haiku 4.5 $0.00004 $0.00057

Measured 8d ago against content hash 94624714324e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

cross-checker 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 8d 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.

plugins/cross-checker/skills/cross-checker/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.

Cross-Checker: Multi-Angle Verification

Never trust a single source. Verify from at least two independent angles before accepting a claim as fact.

The cross-checking method

For any claim, check it against multiple sources:

Source 1: The code itself

Read the actual file. What does the code do? This is the strongest evidence.

Source 2: Tests

What do the tests expect? Tests reveal intended behavior. If a test expects validateToken to return false for expired tokens, that's the designed behavior.

Source 3: Git history

What was the original intent? Git blame and commit messages reveal why code was written. "commit abc123: fix token expiration check to reject tokens older than 24h"

Source 4: Documentation

README, comments, JSDoc, API docs. Do they match the code? If docs say one thing and code does another, the code is truth but the discrepancy matters.

Source 5: Configuration

Config files, environment variables, feature flags. Runtime behavior may differ from what the code looks like.

Source 6: Dependencies

Package versions, API compatibility, deprecated features. A function might exist in the code but be broken due to a dependency update.

Minimum verification standard

Situation Minimum angles needed
Stating a fact to the user 1 (read the code)
Recommending a code change 2 (code + tests or git history)
Security-related claims 3 (code + tests + docs/config)
Production deployment advice 3 (code + config + git history)
"This is safe to delete" 3 (code + grep for references + tests)

Cross-check workflow

  1. Make the initial claim based on what you know
  2. Identify which type of claim it is (fact, recommendation, security)
  3. Check the required number of angles
  4. If sources agree: proceed with confidence
  5. If sources disagree: flag the discrepancy, investigate further
  6. If sources are insufficient: say so, suggest how to get more evidence

Red flags that demand cross-checking

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. 8d ago First seen · 64 lines · 36 tokens per session scan A 94624714324e

Subscribe to this mod's changes

cross-checker is a skill published in the GitHub repository a-ariff/ariff-claude-plugins (14 stars, last pushed 5mo ago), licensed MIT. It adds 36 tokens to every session and 575 once invoked, about $0.0002 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.