OpenChain Selector from Function Signature

openchain/selector-from-signature

Finds the 4-byte selector (and the 32-byte event topic) for an exact signature text such as transfer(address,uint256), by searching the OpenChain signature database. Exact signatures only: wildcards are not accepted. Returns empty objects when the database has no such signature. This is the OpenChain/Sourcify database, a different source from 4byte.directory; the two can disagree.

activeper callv1

Price

$0.0026 per call

You pay the price shown. If a call turns out to cost more than its quote, you pay the actual price, capped at twice the quote. No monthly minimum. Top-ups start at $0.50.

Data source

OpenChain

Function and event signatures from the public OpenChain signature database (https://openchain.xyz). Served by Eden Engine; not an official OpenChain or Sourcify product.

Use it

Five steps: search, inspect, learn, run, settle. No per-tool setup; your agent reaches this tool through the meta-tools it already has.

Connect once and your AI can find and run this tool, and any other it needs.

Install it Create an account

agent

// 1. search: find the tool
omnial_search({ query: "what you need" })

// 2. inspect: price and input schema
omnial_inspect({ tool: "openchain/selector-from-signature" })

// 3. learn: read the usage guide at runtime
omnial_learn({ tool: "openchain/selector-from-signature" })

// 4. run: price the exact call first, then run it
omnial_execute({ tool: "openchain/selector-from-signature", input: { /* see input_schema */ }, dry_run: true })
omnial_execute({ tool: "openchain/selector-from-signature", input: { /* ... */ } })

// 5. settle: the call is charged when it finishes, nothing to do

Not connected yet? Point your MCP client at https://mcp.eden-engine.com/mcp, then copy a config for your client.

Pricing

Every charge this tool can incur.

Charge	Price
Per call	$0.0026

Updated: Oct 21, 2026

Input and output schemas

Input schema

input_schema.json

{
  "type": "object",
  "required": [
    "signature"
  ],
  "properties": {
    "signature": {
      "type": "string",
      "pattern": "^[A-Za-z_][A-Za-z0-9_$]{0,63}\\([A-Za-z0-9_,\\[\\]()]{0,200}\\)$",
      "description": "Exact signature text with parameter types, for example transfer(address,uint256). No wildcards."
    }
  },
  "additionalProperties": false
}

Output schema

output_schema.json

{
  "type": "object",
  "required": [
    "ok",
    "result"
  ],
  "properties": {
    "ok": {
      "type": "boolean"
    },
    "result": {
      "type": "object"
    }
  },
  "description": "Wrapper with an ok flag and the matching signatures.",
  "additionalProperties": true
}