log-ops

log-ops is a skill for Claude Code from 0xDarkMatter/claude-mods. It costs 23 tokens per session (4,604 once invoked), scanned A, original, MIT.

A toolkit for analyzing logs, especially JSONL files where each line is a separate JSON object. It supports extracting data, matching related records, rebuilding timelines, and finding patterns.

In plain words
What is it for?
Use it to inspect agent logs, benchmark output, and other structured records; correlate events across files; reconstruct what happened; and search for recurring patterns.
Why use it?
It reduces the manual work of searching large or unfamiliar logs and connecting events that belong to the same incident or conversation.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: positional $N argument.

Part of the claude-mods plugin — 103 skills, 3 commands, 3 agents, 4 hooks shipped together

Good fit Use it to inspect agent logs, benchmark output, and other structured records; correlate events across files; reconstruct what happened; and search for recurring patterns.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/0xdarkmatter/claude-mods/log-ops
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 0xDarkMatter/claude-mods --skill log-ops
Clone the repo
git clone --depth 1 https://github.com/0xDarkMatter/claude-mods

Made for: Claude Code.

Or install claude-mods, the plugin that ships this one along with the rest of its 103 skills, 3 commands, 3 agents, 4 hooks.

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-ops

README.md
[![agentmods](https://agentmods.dev/badge/skills/0xdarkmatter/claude-mods/log-ops.svg)](https://agentmods.dev/skills/0xdarkmatter/claude-mods/log-ops)
Your own site
<a href="https://agentmods.dev/skills/0xdarkmatter/claude-mods/log-ops"><img src="https://agentmods.dev/badge/skills/0xdarkmatter/claude-mods/log-ops.svg" alt="Measured on agentmods" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,604 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 $0.00023 $0.04604
Opus 5 $0.00012 $0.02302
Sonnet 5 $0.00005 $0.00921
Haiku 4.5 $0.00002 $0.00460

Measured 7d ago against content hash fe4d99e7c744, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

log-ops 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 7d 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-ops/SKILL.md · 459 lines

How it starts

The opening of the file, as written. The whole thing — 459 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Log Operations

Practical patterns for analyzing log files -- especially JSONL format used in agent conversation logs, benchmark outputs, and structured application logs.

Log Format Decision Tree

Unknown Log File
│
├─ Is it one JSON object per line?
│  ├─ Yes ──────────────────────── JSONL
│  │  ├─ Small file (<100MB)
│  │  │  └─ jq for extraction, jq -s for aggregation
│  │  ├─ Large file (100MB-1GB)
│  │  │  └─ rg prefilter then pipe to jq
│  │  └─ Huge file (>1GB)
│  │     └─ split + parallel jq, or jq --stream
│  │
│  └─ No
│     ├─ Is it one large JSON object/array?
│     │  └─ Yes ──────────────── Single JSON
│     │     └─ jq --stream for SAX-style, or jq directly if fits in memory
│     │
│     ├─ Does it have key=value pairs?
│     │  └─ Yes ──────────────── Structured (logfmt / key-value)
│     │     └─ rg for search, awk/sd for extraction, angle-grinder for aggregation
│     │
│     ├─ Does it follow syslog format? (timestamp hostname service[pid]: message)
│     │  └─ Yes ──────────────── Syslog
│     │     └─ rg for search, awk for column extraction, lnav for interactive
│     │
│     ├─ Is it space/tab delimited with consistent columns?
│     │  └─ Yes ──────────────── Column-based (access logs, CSV)
│     │     └─ awk for extraction, mlr for CSV, rg for pattern search
│     │
│     └─ Mixed or unstructured
│        └─ Plain text ─────────── Freeform
│           └─ rg for search, rg -A/-B for context, lnav for exploration

Prerequisites

Required (must be installed):

  • rg (ripgrep) - text search, prefiltering. Install: cargo install ripgrep / choco install ripgrep
  • jq - JSON/JSONL extraction and transformation. Install: brew install jq / choco install jq

Optional (enhanced capabilities, gracefully degraded without):

  • lnav - interactive log exploration with SQL queries. Install: brew install lnav / WSL: apt install lnav
  • agrind (angle-grinder) - pipeline aggregation syntax. Install: cargo install ag
  • mlr (Miller) - CSV/TSV log analysis. Install: brew install miller / choco install miller
  • GNU parallel - parallel processing of split files. Install: brew install parallel

Read the full file on GitHub · 459 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 7d ago First seen · 459 lines · 23 tokens per session scan A fe4d99e7c744

Subscribe to this mod's changes

log-ops is a skill published in the GitHub repository 0xDarkMatter/claude-mods (32 stars, last pushed 14d ago), licensed MIT. It adds 23 tokens to every session and 4,604 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 2026-08-30.

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