event-logging

event-logging is a skill for Claude Code from zaryab2000/decipher-gas-optimizoor. It costs 97 tokens per session (1,619 once invoked), scanned A, original, MIT.

A Solidity review skill that finds historical data stored on-chain when it could be recorded as blockchain events, and checks whether event fields can be filtered efficiently.

In plain words
What is it for?
Use it when reviewing storage arrays, audit trails, price history, action logs, or new event definitions in Solidity contracts.
Why use it?
It helps avoid unnecessary gas costs for data that only needs to be read outside the blockchain, while preserving useful event records.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the decipher-gas-optimizoor plugin — 11 skills, 5 commands, 1 agent shipped together

Good fit Use it when reviewing storage arrays, audit trails, price history, action logs, or new event definitions in Solidity contracts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/zaryab2000/decipher-gas-optimizoor/event-logging
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 zaryab2000/decipher-gas-optimizoor --skill event-logging
Clone the repo
git clone --depth 1 https://github.com/zaryab2000/decipher-gas-optimizoor

Made for: Claude Code.

Or install decipher-gas-optimizoor, the plugin that ships this one along with the rest of its 11 skills, 5 commands, 1 agent.

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 event-logging

README.md
[![agentmods](https://agentmods.dev/badge/skills/zaryab2000/decipher-gas-optimizoor/event-logging/github.svg)](https://agentmods.dev/skills/zaryab2000/decipher-gas-optimizoor/event-logging)
Your own site
<a href="https://agentmods.dev/skills/zaryab2000/decipher-gas-optimizoor/event-logging"><img src="https://agentmods.dev/badge/skills/zaryab2000/decipher-gas-optimizoor/event-logging/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.

agentmods 80×15 button for event-logging

Your own site · 80×15
<a href="https://agentmods.dev/skills/zaryab2000/decipher-gas-optimizoor/event-logging"><img src="https://agentmods.dev/badge/skills/zaryab2000/decipher-gas-optimizoor/event-logging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 97 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,619 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 $0.00097 $0.01619
Opus 5 $0.00048 $0.00809
Sonnet 5 $0.00019 $0.00324
Haiku 4.5 $0.00010 $0.00162

Measured 9d ago against content hash 33670ffe245c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

event-logging 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 9d 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/event-logging/SKILL.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Purpose

Identify storage arrays used solely for off-chain historical data and replace the writes with event emission. Also audit event declarations for missing indexed parameters on fields that callers will filter by.

When to Use

  • Writing or reviewing functions that push to storage arrays
  • Adding new events to a contract
  • Pre-audit review of data retention patterns
  • Reviewing any contract that stores audit trails, price history, or action logs

When NOT to Use

  • When storage data must be read by on-chain code (another contract or the same contract reads the array on-chain)
  • When historical data must survive contract replacement and be directly accessible via eth_getStorageAt without indexer infrastructure
  • When reviewing contracts with no storage arrays and no events

Rationalizations to Reject

Rationalization Why It's Wrong Required Action
"We might need to read this on-chain later" Speculation is not a reason to pay 22,100 gas per push today; if on-chain read is genuinely needed, design for it explicitly Confirm on-chain read requirement before keeping storage
"Events can be lost or missed" Events are part of the transaction receipt, permanent on-chain once included; off-chain indexers (The Graph, Etherscan) reliably capture them Use events for historical data; storage only for current state
"It's just one array" One array pushed once per user action at 1,000 users/day = 22,100,000 gas/day wasted Estimate the volume, not the per-instance cost
"Removing storage might break existing callers" Before removing, verify no external contract reads the array via eth_getStorageAt or ABI calls; confirm off-chain-only access Audit callers, don't assume

Platform Detection

Trigger on any .sol file containing storage array push() calls or event declarations without indexed parameters on address/uint256/bytes32 fields.

Quick Reference

Data type On-chain access needed? Recommendation
Historical array pushes No (only off-chain) Replace with emit Event()
Current state value Yes Keep in storage
Event address/uint256/bytes32 fields used for filtering Add indexed
More than 3 filterable fields Index the 3 most important
string/bytes event field Do NOT index (hashes value, loses original)

Read the full file on GitHub · 164 lines

Files

What ships with it

3 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. 9d ago First seen · 164 lines · 97 tokens per session scan A 33670ffe245c

Subscribe to this mod's changes

event-logging is a skill published in the GitHub repository zaryab2000/decipher-gas-optimizoor (7 stars, last pushed 6mo ago), licensed MIT. It adds 97 tokens to every session and 1,619 once invoked, about $0.0005 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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