Tool Manifest

The metadataURI stored onchain resolves to a JSON manifest that describes your tool. You serve it at /.well-known/ai-tool/<slug>.json on your tool's endpoint origin. Its keccak256 hash (computed over the JCS-canonicalized form) is committed onchain so consumers can verify the manifest hasn't been tampered with.

See the ERC-8257 §2 Tool Manifest for the full normative specification.

Required Fields

Field	Type	Description
`type`	string	Schema version identifier. For v1, use `"https://ercs.ethereum.org/ERCS/erc-8257#tool-manifest-v1"`.
`name`	string	Your tool's name, between 1 and 128 characters (NFC Unicode).
`description`	string	A human-readable description of what your tool does, between 1 and 500 characters (NFC Unicode).
`endpoint`	string	The HTTPS URL where your tool is hosted.
`inputs`	object	A JSON Schema defining your tool's input parameters. Use `{}` if there are none.
`outputs`	object	A JSON Schema defining your tool's output parameters. Use `{}` if there are none.
`creatorAddress`	string	Your lowercase EVM address (`0x...`). This must match the `creator` address recorded in the onchain registry when you call `registerTool`.

Optional Fields

Field	Type	Description
`version`	string	Semantic version (e.g., `"1.0.0"`).
`image`	string	URL for your tool's icon. Use a 1:1 (square) aspect ratio since it's rendered as an avatar or thumbnail in search results and tool cards. Max 2,048 bytes after URL normalization.
`featuredImage`	string	URL for a banner image in 16:9 aspect ratio. To be potentially featured on the featured section of the Tools homepage, you need to include a `featuredImage` in 16:9. Max 2,048 bytes after URL normalization.
`tags`	array	Tags that help users find your tool through search and filtering. Each tag must be lowercase alphanumeric (hyphens allowed), 1 to 32 characters, with a max of 16 tags and no duplicates. See Category Tags below.
`pricing`	array	Payment options for calling your tool. See the Tool Invocation Flow section for details on x402 payments.
`access`	object	Hints that tell agents what access requirements they need before calling your tool. See Access Control for details.
`verifiability`	object	Describes your tool's execution environment and data-handling guarantees. See ERC-8257 §5 for the full specification.

Unknown top-level fields are preserved and not stripped. The manifest hash is computed over the full JCS-canonicalized document as served, so any extra fields you add will be included. If you add custom extension fields, namespace them with a reverse-DNS prefix (e.g., "io.example.myField").

Category Tags

The Tools homepage supports filtering by the following category tags. Use these where applicable so your tool appears in category filters:

Tag	Description
`ai`	AI and machine-learning tools
`defi`	Decentralized finance tools
`nft`	NFT-related tools
`trading`	Trading and market tools
`image`	Image generation and processing tools
`security`	Security and auditing tools

You can also include custom tags beyond these categories. They will still show up on your tool's detail page and are searchable.

Example: Free Tool

{
  "type": "https://ercs.ethereum.org/ERCS/erc-8257#tool-manifest-v1",
  "name": "nft-price-oracle",
  "description": "Returns estimated floor price for any NFT collection.",
  "endpoint": "https://tools.example.com/nft-price-oracle",
  "inputs": {
    "type": "object",
    "properties": {
      "collection": { "type": "string", "description": "Contract address" },
      "chainId": { "type": "integer" }
    },
    "required": ["collection", "chainId"]
  },
  "outputs": {
    "type": "object",
    "properties": {
      "floorPriceEth": { "type": "string" },
      "updatedAt": { "type": "string", "format": "date-time" }
    }
  },
  "version": "1.0.0",
  "image": "https://tools.example.com/nft-price-oracle/icon.png",
  "featuredImage": "https://tools.example.com/nft-price-oracle/featured.png",
  "tags": ["nft", "defi", "oracle"],
  "creatorAddress": "0xabcdefabcdef1234567890abcdefabcdef123456"
}

Example: Paid Tool

{
  "type": "https://ercs.ethereum.org/ERCS/erc-8257#tool-manifest-v1",
  "name": "premium-analytics",
  "description": "Advanced portfolio analytics for NFT holders.",
  "endpoint": "https://tools.example.com/premium-analytics",
  "inputs": {
    "type": "object",
    "properties": {
      "wallet": { "type": "string", "description": "Wallet address to analyze" }
    },
    "required": ["wallet"]
  },
  "outputs": {
    "type": "object",
    "properties": {
      "totalValue": { "type": "string" },
      "breakdown": { "type": "array" }
    }
  },
  "version": "1.0.0",
  "image": "https://tools.example.com/premium-analytics/icon.png",
  "featuredImage": "https://tools.example.com/premium-analytics/featured-16x9.png",
  "tags": ["nft", "trading", "analytics"],
  "pricing": [
    {
      "amount": "20000",
      "asset": "eip155:8453/erc20:0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
      "recipient": "eip155:8453:0xabcdef0123456789abcdef0123456789abcdef01",
      "protocol": "x402"
    }
  ],
  "creatorAddress": "0xabcdef0123456789abcdef0123456789abcdef01"
}

The pricing array uses CAIP-19 asset identifiers and CAIP-10 recipient addresses. See ERC-8257 §3 for the full pricing specification.