What is logging-javascript?

A set of rules for writing JavaScript application logs in a consistent format.

Use it to decide when to log errors and other levels, and to structure details such as error codes, messages, stacks, and impact.

Consistent timestamps, levels, contexts, filenames, messages, and metadata make failures and application behavior easier to understand.

logging-javascript — Cursor rule for Cursor by diegomarino

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.

Clone the repo

git clone --depth 1 https://github.com/diegomarino/awesomic-cursor-rules

Made for: Cursor.

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.

README.md

[![agentmods](https://agentmods.dev/badge/rules/diegomarino/awesomic-cursor-rules/logging-javascript/github.svg)](https://agentmods.dev/rules/diegomarino/awesomic-cursor-rules/logging-javascript)

Your own site

<a href="https://agentmods.dev/rules/diegomarino/awesomic-cursor-rules/logging-javascript"><img src="https://agentmods.dev/badge/rules/diegomarino/awesomic-cursor-rules/logging-javascript/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.

Your own site · 80×15

<a href="https://agentmods.dev/rules/diegomarino/awesomic-cursor-rules/logging-javascript"><img src="https://agentmods.dev/badge/rules/diegomarino/awesomic-cursor-rules/logging-javascript.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Nothing until a file matches its globs; then the whole rule loads.

When invoked 2,995 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.

Model	Per session	Once invoked
Fable 5.1	$0.00000	$0.02995
Opus 5.5	$0.00000	$0.01198
Sonnet 5.5	$0.00000	$0.00599
Haiku 4.5	$0.00000	$0.00299

Measured 1mo ago against content hash f9c6540d2be9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

logging-javascript 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 1mo 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/logging-javascript.mdc · 395 lines

How it starts

The opening of the file, as written. The whole thing — 395 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Logging Guidelines for the Application

1. Log Format Structure

Rule: All logs must follow a consistent format with clear section separation
Format: timestamp ┃ [LEVEL] ┃ [context] ┃ [filename] ┃ message ┃ key1=value1 • key2=value2
Example:

2025-02-08T21:32:48.101Z ┃ [INFO] ┃ [data] ┃ [process-csv.js] ┃ Processing started ┃ file=input.csv • rows=100 • type=user-data

2. Log Levels Usage

ERROR

Critical issues requiring immediate attention

[ERROR] ┃ [database.js] ┃ [db] ┃ Connection failed ┃ error=timeout • retries=3

Purpose: Critical issues requiring immediate attention
When to Use:
- System crashes
- Data corruption
- Security breaches
- Unrecoverable states
- Business critical failures

logger.error(message, {
  filename: string     // Required: filename where this log is triggered
  context: string,      // Required: Error context (e.g., 'db', 'auth')
  error: {             // Required: Error details
    code: string,      // Error classification code
    message: string,   // Error description
    stack?: string,    // Stack trace
    type?: string      // Error type/category
  },
  impact: string,      // Required: Business impact description
  recovery?: string[], // Recommended: Recovery steps
  data?: object,       // Optional: Related data (non-sensitive)
  metrics?: {          // Optional: Performance metrics
    duration?: number,
    attempts?: number
  }
});

logger.error('Database connection failed', {
  filename: 'database_connection.js',
  context: 'db',
  error: {
    code: 'DB_CONN_001',
    message: error.message,
    stack: error.stack,
    type: 'ConnectionError'
  },
  impact: 'System unable to process transactions',
  recovery: [
    'Check database credentials',
    'Verify network connectivity'
  ],
  metrics: {
    duration: 1500,
    attempts: 3
  }
});

WARN

Unexpected conditions that don't stop execution

[WARN] ┃ [auth.js] ┃ [security] ┃ Too many login attempts ┃ user=john • attempts=5

Purpose: Unexpected conditions requiring attention
When to Use:
- Resource thresholds exceeded
- Deprecated feature usage
- Retry attempts
- Performance degradation
- Security concerns

Read the full file on GitHub · 395 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.

1mo ago First seen · 395 lines · 2,995 tokens per session scan A f9c6540d2be9

Subscribe to this mod's changes

logging-javascript is a cursor rule published in the GitHub repository diegomarino/awesomic-cursor-rules (10 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,995 tokens. 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.

Debugging

error-handling-and-validation

A code-quality guide for handling errors, invalid inputs, edge cases, preconditions, logging, and user-friendly error messages.

holtwood/awesome-cursorrules-zh · 185 tokens

css-render-blocking-diagnosis

Cursor rule "css-render-blocking-diagnosis" from adobecom/da-express-milo, covering css render-blocking diagnosis & resolution, critical learning from 98 pagespeed achievement, primary diagnostic protocol, step 1: css blocking symptom recognition and step 2: css loading sequence audit.

adobecom/da-express-milo · 1,102 tokens

logging-javascript