Build, register, and gate AI-callable tool endpoints using the OpenSea Tool Registry (ERC-8257) on Base. Scaffold HTTPS tools with JSON Schema interfaces, register them onchain, gate access via NFT ownership or x402 pay-per-call (USDC), and call gated tools. For querying OpenSea marketplace data use opensea-api instead.
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Build, register, and gate AI-callable tool endpoints using the OpenSea Tool Registry (ERC-8257) on Base.
scope_in)Use opensea-tool-sdk when you need to:
.well-known manifest) for Vercel, Cloudflare, or ExpressauthenticatedFetch), 402 payments (paidFetch), or both (paidAuthenticatedFetch)scope_out, handoff)| Need | Use instead |
|---|---|
| Query NFT/token data, search, collection stats | opensea-api |
| Buy/sell NFTs | opensea-marketplace |
| Swap ERC20 tokens | opensea-swaps |
| Set up wallet signing providers | opensea-wallet |
This SDK is for tool providers and consumers. To query OpenSea marketplace data (floor prices, listings, trades), use the opensea-api skill instead.
| Term | Meaning |
|---|---|
| Tool | An HTTPS endpoint with a JSON Schema interface, discoverable via /.well-known/ai-tool/<slug>.json |
| Manifest | JCS-canonicalized JSON describing the tool's name, endpoint, inputs, outputs, pricing, and access policy |
| ToolRegistry | Onchain contract (Base) where tools are registered with a manifest hash and optional access predicate |
| Access Predicate | An IAccessPredicate contract that gates who can invoke a tool (NFT ownership, subscriptions, composites) |
| x402 | HTTP 402-based pay-per-call protocol (caller signs a USDC TransferWithAuthorization; server settles after execution) |
| SIWE | Sign-In with Ethereum (EIP-4361), used to authenticate callers for predicate-gated tools |
| Facilitator | Third-party service that verifies and settles x402 payments (PayAI or Coinbase CDP) |
Canonical v0.2 deployments — identical CREATE2 address on both chains.
| Contract | Address |
|---|---|
| ToolRegistry (v0.2) | 0x265BB2DBFC0A8165C9A1941Eb1372F349baD2cf1 |
| ERC721OwnerPredicate (v0.2) | 0xc8721c9A776958FfFfEb602DA1b708bf1D318379 |
| ERC1155OwnerPredicate (v0.2) | 0x77373Dc3c1AE9A1e937eF3e5E08F4807D47c7c11 |
npx @opensea/tool-sdk init --runtime vercel # or: cloudflare, expressThis generates:
src/manifest.ts: tool manifest definitionsrc/handler.ts: request handler with input/output schemasapi/index.ts: framework adapter entry pointpublic/llms.txt: agent-readable discovery pageapi/well-known/[slug].ts: serves the manifest at /.well-known/ai-tool/<slug>.jsonimport { defineManifest } from "@opensea/tool-sdk"
export const manifest = defineManifest({
name: "My Tool",
description: "What this tool does",
endpoint: "https://my-tool.example.com/api",
creatorAddress: "0xYOUR_WALLET_ADDRESS",
inputs: {
type: "object",
properties: {
query: { type: "string", description: "Search query" },
},
required: ["query"],
},
outputs: {
type: "object",
properties: {
result: { type: "string" },
},
},
// Optional: add pricing for x402 paywall (see references/x402.md)
// pricing: paywall.pricing,
// Optional: add access requirements (see references/predicate-gating.md)
// access: { logic: "OR", requirements: [...] },
})import { createToolHandler } from "@opensea/tool-sdk"
import { z } from "zod/v4"
import { manifest } from "./manifest.js"
const InputSchema = z.object({ query: z.string() })
const OutputSchema = z.object({ result: z.string() })
export const toolHandler = createToolHandler({
manifest,
inputSchema: InputSchema,
outputSchema: OutputSchema,
// gates: [], // Add gates here (see references/x402.md and references/predicate-gating.md)
handler: async (input) => {
return { result: `Processed: ${input.query}` }
},
})Vercel:
import { toVercelHandler } from "@opensea/tool-sdk"
import { toolHandler } from "../src/handler.js"
export default toVercelHandler(toolHandler)Express:
import { toExpressHandler } from "@opensea/tool-sdk"
import { toolHandler } from "./handler.js"
app.post("/api", toExpressHandler(toolHandler))Cloudflare Workers:
import { toolHandler } from "./handler.js"
export default { fetch: toolHandler }# Set up wallet
export PRIVATE_KEY=0x...
export RPC_URL=https://mainnet.base.org
# Register (open access, no predicate)
npx @opensea/tool-sdk register \
--metadata https://my-tool.example.com/.well-known/ai-tool/my-tool.json \
--network base
# Register with NFT gate (ERC-721 collection)
npx @opensea/tool-sdk register \
--metadata https://my-tool.example.com/.well-known/ai-tool/my-tool.json \
--network base \
--nft-gate 0xCOLLECTION_ADDRESS
# Register with a custom access predicate
npx @opensea/tool-sdk register \
--metadata https://my-tool.example.com/.well-known/ai-tool/my-tool.json \
--network base \
--access-predicate 0xPREDICATE_ADDRESS
# Dry run (no transaction)
npx @opensea/tool-sdk register --metadata ... --network base --dry-runThe CLI:
--metadata URLmanifest.creatorAddress matches your walletToolRegistry.registerTool(metadataURI, manifestHash, accessPredicate)toolId from the ToolRegistered eventimport { ToolRegistryClient, computeManifestHash } from "@opensea/tool-sdk"
import { createWalletFromEnv, walletAdapterToClient } from "@opensea/tool-sdk"
import { base } from "viem/chains"
const adapter = createWalletFromEnv()
const walletClient = await walletAdapterToClient(adapter, base)
const registry = new ToolRegistryClient({
chain: base,
rpcUrl: "https://mainnet.base.org",
walletClient,
})
const { toolId, txHash } = await registry.registerTool({
metadataURI: "https://my-tool.example.com/.well-known/ai-tool/my-tool.json",
manifest, // your ToolManifest object
accessPredicate: "0x0000...0000", // address(0) for open access
})
console.log(`Registered tool ${toolId} in tx ${txHash}`)Tools can be gated three ways:
| Gate | Mechanism | Reference |
|---|---|---|
| x402 paywall | Pay-per-call (USDC, EIP-3009) | references/x402.md |
| Predicate gate | Onchain check (NFT, subscription, composite) | references/predicate-gating.md |
| Combined | SIWE auth and payment (predicate first, then x402) | references/predicate-gating.md |
For deployed predicate addresses, requirement encodings, and SDK helpers like describeToolAccess / decodeRequirement, see references/known-predicates.md.
The SDK supports multiple wallet providers via @opensea/wallet-adapters. Set environment variables and the SDK auto-detects the provider. See the opensea-wallet skill for the full provider table, env vars, setup walkthroughs, and signing-policy configuration.
import { createWalletFromEnv } from "@opensea/tool-sdk"
const adapter = createWalletFromEnv()
const address = await adapter.getAddress()For Bankr (external signer):
import { createBankrAccount } from "@opensea/tool-sdk"
const account = await createBankrAccount("your-bankr-api-key")
// Use with authenticatedFetch or paidAuthenticatedFetch| Code | Meaning | Action |
|---|---|---|
| 200 | Success | Parse the JSON body per the manifest's outputs schema |
| 400 | Invalid input | Fix request body to match the manifest's inputs schema |
| 401 | Missing/invalid SIWE auth | Sign a SIWE message and include Authorization: SIWE <token> |
| 402 | Payment required | Read body.accepts[0] for payment requirements, sign and retry with X-Payment |
| 403 | Access denied | Inspect body.predicate to discover what's needed; acquire the required token/subscription |
| 405 | Method not allowed | Use POST |
| 500 | Internal tool error | Retry or contact the tool creator |
| 502 | Predicate/facilitator error | The upstream predicate or payment facilitator misbehaved; retry later |
| Command | Purpose |
|---|---|
init | Scaffold a new tool project |
validate | Validate a manifest file |
hash | Compute the JCS keccak256 hash of a manifest |
export | Export the manifest as JSON |
register | Register a tool onchain |
update-metadata | Update a tool's metadata URI and manifest hash onchain |
inspect | Look up a tool's onchain config by ID |
verify | Verify a manifest against its onchain hash |
deploy | Deploy a tool to Vercel |
auth | Call a predicate-gated tool (SIWE) |
pay | Call an x402-paid tool (USDC) |
smoke | Auto-detect gate type and call |
dry-run-gate | Simulate an x402 gate check locally |
dry-run-predicate-gate | Simulate a predicate gate check locally |
All CLI commands accept --wallet-provider privy|turnkey|fireblocks|bankr|private-key or auto-detect from env vars.
# 1. Scaffold
npx @opensea/tool-sdk init --runtime vercel
# 2. Edit src/manifest.ts and src/handler.ts with your logic
# 3. Deploy
npx @opensea/tool-sdk deploy
# 4. Register (open access)
PRIVATE_KEY=0x... npx @opensea/tool-sdk register \
--metadata https://my-tool.vercel.app/.well-known/ai-tool/my-tool.json \
--network base
# 5. Call
curl -X POST https://my-tool.vercel.app/api \
-H "Content-Type: application/json" \
-d '{"query": "hello"}'# Server: add paywall gate (see references/x402.md)
# Call via CLI:
PRIVATE_KEY=0x... npx @opensea/tool-sdk pay \
https://my-tool.vercel.app/api \
--body '{"query": "hello"}'# Register with NFT gate
PRIVATE_KEY=0x... npx @opensea/tool-sdk register \
--metadata https://my-tool.vercel.app/.well-known/ai-tool/my-tool.json \
--network base \
--nft-gate 0xCOLLECTION
# Server: add predicateGate (see references/predicate-gating.md)
# Call via CLI:
PRIVATE_KEY=0x... RPC_URL=https://mainnet.base.org \
npx @opensea/tool-sdk auth \
https://my-tool.vercel.app/api \
--body '{"query": "hello"}'# Server: add both predicateGate and paywall.gate (see references/predicate-gating.md)
# Call via CLI:
PRIVATE_KEY=0x... RPC_URL=https://mainnet.base.org \
npx @opensea/tool-sdk smoke \
--endpoint https://my-tool.vercel.app/api \
--expect 200references/x402.md: pay-per-call protocol, server-side paywall, paidFetchreferences/predicate-gating.md: SIWE-based access control, combined gatesreferences/known-predicates.md: deployed predicate contracts and SDK helpers10f23f8
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