ERC-8257 Agent Tool Registry

DraftERCcreated 2026-04-17requires EIP-150, ERC-165, EIP-712, ERC-1967

Minimal onchain registry for AI agent tools with extensible predicate-based access control

Authors: Cody Sears (@CodySearsOS), Ryan Ghods (@ryanio)

ERC-165 interface ids

Computed here as the XOR of the selectors each interface defines.

`0x9148e6ca`	`deregisterTool(uint256)`
`0xcb429230`	`erc1155Holding()`
`0xbdf8c428`	`erc721Holding()`
`0x1ce77540`	`getRequirements(uint256)`	view
`0xa0178453`	`getToolConfig(uint256)`	view
`0xa7e3775b`	`hasAccess(uint256,address,bytes)`	view
`0x06fdde03`	`name()`	view
`0xfe1d0b16`	`registerTool(string,bytes32,address)`
`0xde24a6d2`	`setAccessPredicate(uint256,address)`
`0x44387cc2`	`subscription()`
`0xfaf23b23`	`toolCount()`	view
`0x2361abf3`	`tryHasAccess(uint256,address,bytes)`	view
`0xccca3bf0`	`updateToolMetadata(uint256,string,bytes32)`
`0x54fd4d50`	`version()`	view

0x01ffc9a7 supportsInterface(bytes4) ERC-165

Topic0 is the keccak256 hash of the signature, which is what a log filter matches on.

`0xe7be7fd3c802f61682f56ba817276b1cc81fbee7cb50705c8ed7952811dac397`	`ToolRegistered(uint256,address,address,string,bytes32)`
`0x14f92d1aaaea2df5f884f2fd8dbb6ea7cad1784ffaac2d8fd594f107d719a414`	`ToolMetadataUpdated(uint256,string,bytes32)`
`0x53e2d3a37877f4a367d09cdba706178d3c6414a15d642294300c65a8037dd6ff`	`AccessPredicateUpdated(uint256,address)`
`0x9add33e854e243f868ff7cacac076d65b1d56fb593e2bb891e76e2e8d5ddd034`	`ToolDeregistered(uint256)`

`0xb73d6f8b`	`ToolNotFound(uint256)`
`0xd594d2e7`	`NotToolCreator(uint256,address)`
`0xeec403f0`	`InvalidMetadataURI()`
`0x03d0cf2a`	`InvalidManifestHash()`
`0x4c8ce4df`	`InvalidAccessPredicate(address)`
`0x0bf47976`	`ToolIsDeregistered(uint256)`