etherscan-transaction-debugger

A tool for explaining one or two blockchain transactions on Etherscan, a public website that records activity on Ethereum-compatible networks. It uses transaction, contract, token, label, and available call data with links that people can check.

In plain words
What is it for?
Use it to investigate why a transaction failed, identify contracts and internal calls, trace asset movement, inspect proxy implementations, or prepare explanations for developers, users, support teams, or security reviews.
Why use it?
It turns a transaction hash into an understandable account of the result, calls, failures, and asset movements without hiding the underlying evidence.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/etherscan/skills/etherscan-transaction-debugger
Any agent
npx skills add etherscan/skills --skill etherscan-transaction-debugger
Clone the repo
git clone --depth 1 https://github.com/etherscan/skills

Made for: Claude Code, Codex.

Per session 155 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,139 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 $0.00155 $0.02139
Opus 5 $0.00077 $0.01069
Sonnet 5 $0.00031 $0.00428
Haiku 4.5 $0.00015 $0.00214

Measured 2d ago against content hash ec9c45e51693, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

etherscan-transaction-debugger 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 2d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/collect_transaction_data.py, scripts/summarize_transaction.py), 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.

skills/etherscan-transaction-debugger/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Etherscan Transaction Debugger

Turn Etherscan's transaction, contract, token, and label data into a clear execution story that users can verify directly on the explorer. Preserve raw hashes and addresses, make important claims auditable, and never make trace completeness sound stronger than the available data.

Inputs

Require a 32-byte transaction hash. Accept a second hash for a focused comparison.

Determine the chain from the user, a chain-specific explorer URL, transaction data, or surrounding context. Ask only when the hash is valid on multiple candidate chains or cannot be found. Default to Ethereum only when no chain clue exists, and state the assumption.

Treat the expected outcome, protocol name, and requested audience as optional. Infer a useful explanation level when omitted:

  • simple: short, nontechnical outcome.
  • standard: outcome, important calls, and asset changes.
  • developer: decoded calldata, call semantics, proxy path, and failure evidence.
  • support: customer-ready explanation plus escalation notes.
  • security: permissions, callbacks, delegate calls, recipients, and evidence-backed anomalies.

Core Workflow

  1. Validate the hash and resolve the chain.
  2. Use Etherscan as the primary data and verification surface. Collect live transaction, receipt, status, internal-operation, contract, ABI, verified source, proxy, label, token, and explorer-link evidence. Prefer the Etherscan CLI when installed; use scripts/collect_transaction_data.py for a reproducible evidence bundle. Read references/evidence-collection.md when collection fails, the CLI is unavailable, or deep trace data is needed.
  3. Establish facts before interpreting intent: sender, destination, status, block time, top-level value and calldata, gas used, effective gas price, logs, created contract, and returned errors.
  4. Decode the top-level method and important logs with verified ABIs. Resolve proxy and implementation roles before attributing behavior. Read references/execution-semantics.md for proxies, call types, callbacks, asset movements, and common patterns.
  5. Build only the execution path supported by evidence. Label inferred edges and omitted low-value details. Never call Etherscan internal transactions a complete call trace.
  6. Reconcile native, ERC-20, ERC-721, and ERC-1155 movements; approvals; operator permissions; ownership or role changes; and proxy upgrades. Calculate the execution gas fee as gasUsed * effectiveGasPrice using integers. Include L1 data or blob fees when the receipt provides them, and report a total transaction fee only when every applicable component is known.
  7. If the transaction failed or contains a suspicious child failure, read references/failure-analysis.md and identify the narrowest supported root cause.
  8. Cross-check the narrative against the receipt status, logs, values, addresses, and trace. Read references/reporting.md before producing security, support, comparison, or low-confidence reports.
  9. Create an Etherscan evidence trail: link the transaction and each important address, contract, implementation, token, and relevant explorer view on the correct Etherscan-family explorer.

Read the full file on GitHub · 118 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.

  1. 2d ago First seen · 118 lines · 155 tokens per session scan A ec9c45e51693

Subscribe to this mod's changes

etherscan-transaction-debugger is a skill published in the GitHub repository etherscan/skills (21 stars, last pushed 15d ago), licensed MIT. It adds 155 tokens to every session and 2,139 once invoked, about $0.0008 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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