tx-explain

${var} — Transaction hash (0x..., 66 chars) on Base. Required. If empty, log TX_EXPLAIN_NO_TARGET and exit cleanly (no notify).

Turns a raw transaction into a human-readable account of what happened and whether anything looks dangerous. Runs keyless on public endpoints.

Config

• Target = ${var}. Chain = Base (chainid=8453, explorer basescan.org).
• ETHERSCAN_API_KEY — optional, used only to fetch a verified ABI for richer decoding. Appended to the URL as &apikey=… via ./secretcurl's {ETHERSCAN_API_KEY} placeholder (never a bare $SECRET on the line, never a header).

Steps

1. Fetch tx + receipt

TX="${var}"
curl -m 10 -s -X POST "https://mainnet.base.org" -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["'"$TX"'"],"id":1}' | jq '.result'
curl -m 10 -s -X POST "https://mainnet.base.org" -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getTransactionReceipt","params":["'"$TX"'"],"id":1}' | jq '.result'

Record: from, to, native value, status (success/revert), gas used, block/time.

2. Decode the method

Take the first 4 bytes of input (the selector). Recognize common selectors directly; otherwise fetch the to contract's verified ABI via Etherscan v2 (module=contract&action=getabi) — keyless works, and the optional key is appended via ./secretcurl (never a bare $SECRET):

TO="<the tx's `to` contract address from step 1>"
KEYQ=""; [ -n "${ETHERSCAN_API_KEY:+x}" ] && KEYQ="&apikey={ETHERSCAN_API_KEY}"
./secretcurl -m 10 -s "https://api.etherscan.io/v2/api?chainid=8453&module=contract&action=getabi&address=${TO}${KEYQ}" | jq -r '.result'

Common selectors:

Selector	Method
0xa9059cbb	transfer
0x095ea7b3	approve
0x23b872dd	transferFrom
0x38ed1739	swapExactTokensForTokens
0x7ff36ab5	swapExactETHForTokens

3. Decode token movements from logs