evm_selector_decode
Decode EVM function selectors, calldata and event topics: looks up 4-byte selectors (or 32-byte event topics) in 4byte.directory plus a built-in table of well-known signatures, re-hashes every candidate with Keccak-256 to drop bad entries, and for full calldata ABI-decodes the arguments (address ...
This record as markdown: /tools/com-it-scorptech-x402/evm-selector-decode.md
What evm_selector_decode does on ScorpTech x402 API
AI agents call evm_selector_decode to permanently remove resources in ScorpTech x402 API, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
| Parameter | Type | Required | Description |
|---|---|---|---|
limit | integer | — | Max candidates 1-50 (default 10) |
topic | string | — | 32-byte event topic0 hash |
calldata | string | — | Full transaction input data (0x...), decoded against the candidates |
selector | string | — | 4-byte function selector, e.g. 0xa9059cbb |
signature | string | — | A signature like transfer(address,uint256) to hash into its selector/topic |
Parameters from the server's own tool schema.
Why evm_selector_decode is rated Critical
An AI agent that decides to call evm_selector_decode doesn't hesitate, doesn't double-check, and doesn't stop at one. Whatever it removes from ScorpTech x402 API is gone. There is no undo for destructive operations.
Attacks that exploit this kind of access
The rule that runs evm_selector_decode safely
PolicyLayer is an MCP gateway: it sits between your AI agents and ScorpTech x402 API, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For evm_selector_decode, this is the rule to start with:
evm_selector_decode is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect ScorpTech x402 API, apply this rule, and every evm_selector_decode call is checked against it from then on.
Questions about evm_selector_decode
Decode EVM function selectors, calldata and event topics: looks up 4-byte selectors (or 32-byte event topics) in 4byte.directory plus a built-in table of well-known signatures, re-hashes every candidate with Keccak-256 to drop bad entries, and for full calldata ABI-decodes the arguments (address with EIP-55 checksum, uint/int as exact decimal strings, bool, bytes, string, arrays, tuples), ranking candidates that decode cleanly first. Also computes the selector/topic for a given signature. Price: $0.005 USDC per successful call (x402, Solana). Same tool over HTTPS: GET https://scorptech.it.com/api/x402/v1/evm-selector-decode. It is categorised as a Destructive tool in the ScorpTech x402 API MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
evm_selector_decode accepts 5 parameters: limit, topic, calldata, selector, signature. The full parameter table on this page comes from the server's own tool schema.
Register the ScorpTech x402 API MCP server in PolicyLayer and add a rule for evm_selector_decode: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches ScorpTech x402 API. Nothing to install.
evm_selector_decode is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the evm_selector_decode rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for evm_selector_decode. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
evm_selector_decode is provided by the ScorpTech x402 API MCP server (https://scorptech.it.com/api/x402/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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