trace-tx

Fetches the full execution trace for an EVM transaction via debug_traceTransaction. The trace reveals the complete call tree: every internal CALL/DELEGATECALL/CREATE, gas consumed at each step, input/output data, and any revert reasons.

Usage

~/.claude/skills/trace-tx/scripts/trace_tx.sh [-o <output_file>] <TX_HASH> <RPC_URL> [TRACER] [onlyTopCall]

• Use the RPC URL the user supplied.
• Or if ALCHEMY_API_KEY is set, construct the Alchemy URL: https://<chain-slug>.g.alchemy.com/v2/$ALCHEMY_API_KEY and use it as the RPC URL. Common slugs: "Ethereum"/"ETH" → eth-mainnet, "Arbitrum"/"Arb" → arb-mainnet, "Base" → base-mainnet, "Optimism"/"OP" → opt-mainnet, "Polygon"/"MATIC" → polygon-mainnet, "BSC"/"BNB Chain" → bnb-mainnet, "Sepolia" → eth-sepolia. Find full slug list in references/rpc_urls.md only when necessary.
• If neither is available, find an RPC URL that supports debug_traceTransaction for the specific tx.
• Default tracer: callTracer (nested call tree — best for most tasks). Also supports prestateTracer and raw opcode trace.

Workflow

Use -o to write the trace to a file — traces can be megabytes: