004-assertion-patterns

A set of rules for recording checks that confirm whether a web page shows the expected result. It can notice changing messages such as alerts, toasts, and dialogs, or let someone record a check with a keyboard shortcut.

In plain words
What is it for?
Use it when capturing browser tests that need to check success messages, errors, warnings, dialogs, or other page feedback.
Why use it?
It reduces the need to manually write down every visible result during browser testing. It also turns recorded checks into verification steps in a consistent way.

Cursor rule

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 rules/azam-sdet/10xquality/004-assertion-patterns
Clone the repo
git clone --depth 1 https://github.com/azam-sdet/10xquality
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,614 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 $0.00023 $0.01614
Opus 5 $0.00012 $0.00807
Sonnet 5 $0.00005 $0.00323
Haiku 4.5 $0.00002 $0.00161

Measured 2d ago against content hash 37ea41b2dd66, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

004-assertion-patterns 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 2d 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.

rules/004-assertion-patterns.mdc · 147 lines

How it starts

The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Assertion Capture Patterns

Assertions are captured in two ways: automatic (MutationObserver) and manual (keyboard shortcut). This document describes detection logic and conversion rules for generating verification steps.

Auto-Assertion Detection

MutationObserver Selectors

The recorder observes DOM mutations and matches elements against these selectors to detect assertion-worthy content:

Category Selectors
ARIA roles [role="alert"], [role="status"], [role="dialog"], [role="alertdialog"]
Toast/notification .toast, .Toast, .Toastify, .Toastify__toast, .notification, .Notification
Snackbar .snackbar, .Snackbar, .MuiSnackbar-root
Alert .alert, .Alert, .MuiAlert-root
Modal .modal, .Modal, .MuiModal-root, .dialog, .Dialog
Message classes .success-message, .error-message, .warning-message, .info-message
Feedback .feedback, .flash, .banner
Data attributes [data-test*="Toast"], [data-test*="Alert"], [data-test*="Modal"], [data-test*="Snackbar"], [data-test*="Message"], [data-testid*="toast"], [data-testid*="alert"], [data-testid*="modal"], [data-testid*="snackbar"], [data-testid*="message"]

Observer Configuration

observer.observe(document.body, {
  childList: true,
  subtree: true,
  attributes: true,
  attributeFilter: ['class', 'role', 'style', 'hidden', 'aria-hidden'],
});
  • childList: Detects new nodes added to the DOM
  • subtree: Watches descendants
  • attributes: Detects attribute changes (e.g., class toggles that show/hide messages)
  • attributeFilter: Limits observed attributes for performance

Classification Logic

When an element matches the assertion selectors, it is classified by role, class names, and text content:

Condition Classification
role="alert" or role="alertdialog" alert
role="status" status
role="dialog" dialog
Class/text contains "error", "failed" error
Class/text contains "success", "created", "saved" success
Class/text contains "warning", "warn" warning
Class/text contains "info", "notification" info
Class contains "toast", "snackbar" toast
Class contains "modal", "dialog" dialog
Default notification

Read the full file on GitHub · 147 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. 2d ago First seen · 147 lines · 23 tokens per session scan A 37ea41b2dd66

Subscribe to this mod's changes

004-assertion-patterns is a cursor rule published in the GitHub repository azam-sdet/10xquality (2 stars, last pushed 5mo ago), licensed MIT. It adds 23 tokens to every session and 1,614 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.