log-pattern-scan

log-pattern-scan is a skill for Claude Code from gertsylvest/meta-team. It costs 40 tokens per session (691 once invoked), scanned A, original, MIT.

A scanner for Claude Code session logs stored as JSONL files, a text format with one JSON record per line. It looks for loops, errors, costly turns, trial-and-error patterns, or summaries, including work done by subagents.

In plain words
What is it for?
Use it to inspect one session or a project’s sessions and find repeated actions, failures, inefficient turns, or trial-and-error behavior.
Why use it?
The main session log may omit much of the activity performed by subagents, making problems look smaller than they are.

Skill for Claude Code

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

Good fit Use it to inspect one session or a project’s sessions and find repeated actions, failures, inefficient turns, or trial-and-error behavior.

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Install with agentmods
npx agentmods add skills/gertsylvest/meta-team/log-pattern-scan
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 gertsylvest/meta-team --skill log-pattern-scan
Clone the repo
git clone --depth 1 https://github.com/gertsylvest/meta-team

Made for: Claude Code.

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-pattern-scan

README.md
[![agentmods](https://agentmods.dev/badge/skills/gertsylvest/meta-team/log-pattern-scan.svg)](https://agentmods.dev/skills/gertsylvest/meta-team/log-pattern-scan)
Your own site
<a href="https://agentmods.dev/skills/gertsylvest/meta-team/log-pattern-scan"><img src="https://agentmods.dev/badge/skills/gertsylvest/meta-team/log-pattern-scan.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 691 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 $0.00040 $0.00691
Opus 5 $0.00020 $0.00345
Sonnet 5 $0.00008 $0.00138
Haiku 4.5 $0.00004 $0.00069

Measured 8d ago against content hash 5aa4f662be5d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

log-pattern-scan 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scan.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

library/skills/log-pattern-scan/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Log Pattern Scan

Scan one or more Claude Code JSONL session transcript files for behavioral inefficiency patterns.

Instructions

Arguments are in $ARGUMENTS:

  • First arg: path to a .jsonl file, or a project root path (scans all sessions for that project)
  • Second arg (optional): scan type — all (default), errors, loops, expensive, trialerror, summary

If no arguments are provided, ask the user before proceeding.

When given a project root, the scan recurses into subagent sidechains (<session>/subagents/agent-*.jsonl, marked isSidechain: true) as well as the top-level session transcripts. This matters: the orchestrator/main transcript records only ~15% of tool activity — the bulk of tool calls, errors, and loops happen inside subagents. Scanning only the top level can undercount errors by an order of magnitude. Each finding is headed by its path relative to the project folder, so sidechain findings are attributable to the agent that produced them.

Run the scan

The scan script lives alongside this file. Run it directly:

bash "$(dirname "$0")/scan.sh" <first-arg> <second-arg>

Scan types

Type What it detects
summary Total lines, tool calls, errors, token totals per session
errors Tool calls that returned is_error: true
loops Same tool called 3+ times consecutively, or same tool+input repeated 3+ times across the session
expensive Turns with >2000 output tokens (EXPENSIVE-OUTPUT) or >10000 new cache tokens (EXPENSIVE-CONTEXT)
trialerror 3+ edits to the same file (CHURN), 3+ identical bash commands (REPEAT-CMD), sessions >200 messages (LONG SESSION)
all All of the above

Output prefixes

Each finding is prefixed for easy parsing:

Prefix Meaning
ERROR Failed tool call
LOOP Consecutive same-tool repetition
REPEAT Same tool+input repeated across session
EXPENSIVE-OUTPUT High output token turn
EXPENSIVE-CONTEXT Large new context loaded in one turn
CHURN Repeated edits to same file
REPEAT-CMD Repeated identical bash command
LONG SESSION Session exceeds 200 messages
OK No issues found for that scan type

Read the full file on GitHub · 66 lines

Files

What ships with it

1 file 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. 8d ago First seen · 66 lines · 40 tokens per session scan A 5aa4f662be5d

Subscribe to this mod's changes

log-pattern-scan is a skill published in the GitHub repository gertsylvest/meta-team (5 stars, last pushed 29d ago), licensed MIT. It adds 40 tokens to every session and 691 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 2026-08-31.

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