log-analyzer

log-analyzer is a skill for Claude Code, Codex from JansenAnalytics/claudex. It costs 37 tokens per session (480 once invoked), scanned A, original, MIT.

A tool for reading application log files and finding patterns, errors, timing links, and unusual activity. It recognises several common log formats, including JSON, Nginx, Node.js, and Python logs.

In plain words
What is it for?
Use it to investigate production incidents, compare errors with deployments, find frequent failures, and create filtered or summarised log reports.
Why use it?
It reduces the manual work of searching through large, noisy logs when an application has a problem. Grouping similar errors and filtering by time or severity helps narrow down likely causes.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python3 scripts/log-parse.py --input app.log.

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/JansenAnalytics/claudex
agentmods
npx agentmods add skills/jansenanalytics/claudex/log-analyzer

Made for: Claude Code, Codex.

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 log-analyzer

README.md
[![agentmods](https://agentmods.dev/badge/skills/jansenanalytics/claudex/log-analyzer.svg)](https://agentmods.dev/skills/jansenanalytics/claudex/log-analyzer)
Your own site
<a href="https://agentmods.dev/skills/jansenanalytics/claudex/log-analyzer"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/log-analyzer.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 480 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 5.1 $0.00037 $0.00480
Opus 5 $0.00018 $0.00240
Sonnet 5 $0.00007 $0.00096
Haiku 4.5 $0.00004 $0.00048

Measured 3d ago against content hash befcd17ecad5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

log-analyzer 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 3d 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.

skills/log-analyzer/SKILL.md · 61 lines

What it actually says

log-analyzer

Parse and analyze application logs: pattern matching, error extraction, correlation with timestamps, frequency analysis, anomaly detection. Use when: diagnosing production issues, finding error patterns in logs, correlating errors with deployments, analyzing log frequency/trends, or filtering noise from large log files.

Scripts

log-parse.py

Universal log parser with auto-format detection and filtering.

# Basic usage
python3 scripts/log-parse.py --input app.log

# Filter by level
python3 scripts/log-parse.py --input app.log --level error,warn

# Time-based filter
python3 scripts/log-parse.py --input app.log --since "2024-01-15 14:00"

# Pattern matching
python3 scripts/log-parse.py --input app.log --grep "database" --exclude "health"

# Markdown output
python3 scripts/log-parse.py --input app.log --level error --format markdown

Auto-detects: JSON logs, syslog, nginx access/error, Node.js console, Python logging.

error-summary.py

Aggregates and groups errors from log files.

python3 scripts/error-summary.py --input app.log --top 20
python3 scripts/error-summary.py --input app.log --input server.log --top 10

Groups by fuzzy-matched error message (strips variable parts like IDs, timestamps). Reports: unique count, first/last occurrence, frequency, sample stack trace.

log-correlator.sh

Correlates events across multiple log files within a time window.

bash scripts/log-correlator.sh --logs "app.log,nginx.log,system.log" --time "2024-01-15 14:32" --window 5m

References

  • references/log-formats.md — Common log format patterns with regex
  • references/troubleshooting-guide.md — Systematic troubleshooting with logs
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. 3d ago First seen · 61 lines · 37 tokens per session scan A befcd17ecad5

Subscribe to this mod's changes

log-analyzer is a skill published in the GitHub repository JansenAnalytics/claudex (5 stars, last pushed 2mo ago), licensed MIT. It adds 37 tokens to every session and 480 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 2026-09-03.