Opensea Tool Sdk

OpenSea Tool SDK

Build, register, and gate AI-callable tool endpoints using the OpenSea Tool Registry (ERC-8257) on Base.

When to use this skill (scope_in)

Use opensea-tool-sdk when you need to:

• Scaffold an AI-callable tool endpoint (HTTPS, JSON Schema, .well-known manifest) for Vercel, Cloudflare, or Express
• Register a tool onchain on the Base ToolRegistry so other agents can discover it
• Gate access via x402 pay-per-call (USDC) or predicates (ERC-721/ERC-1155 ownership, subscriptions, trait gating, ERC-20 balance, composites)
• Call a gated or paid tool: 402 payments (paidFetch), predicate-gated auth (eip3009AuthenticatedFetch), or both (paidAuthenticatedFetch)
• Search and discover registered tools via the OpenSea REST API

When NOT to use this skill (scope_out, handoff)

This SDK is for tool providers and consumers. To query OpenSea marketplace data (floor prices, listings, trades), use the opensea-api skill instead.

Concepts

Important Constraints

One tool = one endpoint. Each tool registration represents a single REST API endpoint with a singular focus and intention. The endpoint URL in your manifest should point to a specific API route that performs one well-defined operation (e.g., POST /api/price-check or POST /api/translate), not a generic HTML page, documentation site, or multi-purpose URL. Think of each registered tool the same way you think of an individual REST API endpoint. It should accept a specific input, perform a specific action, and return a specific output.

Origin binding: manifest and endpoint must share the exact same origin. Your .well-known/ai-tool/<slug>.json manifest and your tool's invocation endpoint must be served from the exact same origin (identical scheme, host, and port per RFC 6454). Subdomains do not count as the same origin. example.com and api.example.com are different origins. This is enforced at registration time. If the manifest origin and endpoint origin don't match exactly, the tool will be rejected and marked as deregistered.

• Valid: manifest at https://my-tool.example.com/.well-known/ai-tool/my-tool.json, endpoint at https://my-tool.example.com/api/my-tool
• Invalid: manifest at https://example.com/.well-known/ai-tool/my-tool.json, endpoint at https://api.example.com/api/my-tool

If you need your API on a subdomain, serve the manifest from that same subdomain (e.g., both on api.example.com).

Deployed Contracts (Ethereum mainnet, Base, Shape, Abstract, Monad, Robinhood Chain)

Canonical v0.2 deployments — identical CREATE2 address on every supported chain.

Tool Discovery [Beta]

Search or look up registered tools via the OpenSea REST API. Requires OPENSEA_API_KEY.

# Reuse OPENSEA_API_KEY if already set; otherwise fetch an instant free-tier key
# (no signup — 600/h read, 30/h write, 7-day expiry) and SAVE it for reuse.
if [ -z "${OPENSEA_API_KEY:-}" ]; then
  KEY_FILE="${OPENSEA_CONFIG_DIR:-$HOME/.opensea}/api_key"
  if [ -s "$KEY_FILE" ]; then
    export OPENSEA_API_KEY=$(cat "$KEY_FILE")          # reuse cached key
  else
    api_key=$(curl -s -X POST https://api.opensea.io/api/v2/auth/keys | jq -r '.api_key')
    mkdir -p "$(dirname "$KEY_FILE")"
    (umask 077; printf '%s\n' "$api_key" > "$KEY_FILE")  # save before using it
    export OPENSEA_API_KEY="${api_key}"
  fi
fi

Always save a fetched instant key and reuse it rather than re-fetching. The opensea-api skill ships an auth/opensea-resolve-key.sh helper that does this (env → cached file → fetch + save); see its "API key resolution" section. For higher rate limits, create a full key at Settings → Developer.

List tools: GET /api/v2/tools (docs)

Search tools: GET /api/v2/tools/search (docs)

Get a tool: GET /api/v2/tools/{registry_chain}/{registry_addr}/{tool_id} (docs)

# List tools sorted by newest
curl -s "https://api.opensea.io/api/v2/tools?sort_by=newest&limit=10" \
  -H "x-api-key: $OPENSEA_API_KEY" | jq

# List tools filtered by type
curl -s "https://api.opensea.io/api/v2/tools?type=open&sort_by=oldest" \
  -H "x-api-key: $OPENSEA_API_KEY" | jq

# Search tools by keyword
curl -s "https://api.opensea.io/api/v2/tools/search?query=nft" \
  -H "x-api-key: $OPENSEA_API_KEY" | jq

# Get a specific tool on Base
curl -s "https://api.opensea.io/api/v2/tools/8453/0x265BB2DBFC0A8165C9A1941Eb1372F349baD2cf1/1" \
  -H "x-api-key: $OPENSEA_API_KEY" | jq

# Filter by access type
curl -s "https://api.opensea.io/api/v2/tools/search?access_type=open&limit=10" \
  -H "x-api-key: $OPENSEA_API_KEY" | jq

1. Create a Tool

1a. Scaffold a project

npx @opensea/tool-sdk init --runtime vercel   # or: cloudflare, express

This generates:

• src/manifest.ts — tool manifest definition
• src/handler.ts — request handler with input/output schemas
• api/index.ts — framework adapter entry point
• public/llms.txt — agent-readable discovery page
• api/well-known/[slug].ts — serves the manifest at /.well-known/ai-tool/<slug>.json

1b. Define the manifest

import { 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: [...] },
})

1c. Write the handler

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}` }
  },
})

1d. Wire up the adapter

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 }

2. Register a Tool Onchain

2a. Via CLI

# 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 an 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-run

The CLI:

1. Fetches the manifest from --metadata URL
2. Validates the manifest schema
3. Verifies manifest.creatorAddress matches your wallet
4. Computes the JCS keccak256 manifest hash
5. Calls ToolRegistry.registerTool(metadataURI, manifestHash, accessPredicate)
6. Returns the toolId from the ToolRegistered event

2b. Via SDK (programmatic)

import { 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) = open access
})

console.log(`Registered tool ${toolId} in tx ${txHash}`)

3. Gating tool access

Tools can be gated three ways:

For deployed predicate addresses, requirement encodings, and SDK helpers like describeToolAccess / decodeRequirement, see references/known-predicates.md.

4. Wallet Setup

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.

For any provider, RPC_URL (or the --rpc-url flag) sets the RPC endpoint for onchain reads and writes. When neither is set, CLI commands fall back to the network's default public RPC, which can be slow or rate-limited.

import { createWalletFromEnv } from "@opensea/tool-sdk"

// Auto-detects: Privy > Fireblocks > Turnkey > Bankr > PrivateKey
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 eip3009AuthenticatedFetch or paidAuthenticatedFetch

5. Response Codes

6. Quick Reference: CLI Commands

All CLI commands accept --wallet-provider privy|turnkey|fireblocks|private-key or auto-detect from env vars.

The manifest is hashed as served (ERC-8257 §2). The registry hash is the JCS keccak256 of the full manifest document, including any namespaced extension fields. Nothing is stripped and no defaults are injected before hashing, so a hash computed by any RFC 8785 implementation agrees with the SDK and the backend. The schema is open: extension fields MUST be namespaced (reverse-DNS, e.g. io.opensea.paymentHint, or the legacy x- prefix); validate, hash, and register warn about bare un-namespaced extension fields, since those risk colliding with future normative fields.

7. Usage Tracking

Tool-sdk reports usage to OpenSea's analytics endpoint (POST /api/v2/tools/usage) for each successful call. It reports the verified caller: the on-chain payer for paid x402 calls, or the caller's own EIP-3009 authorization for predicateGate-authenticated calls. A tool server never signs on the caller's behalf.

usageReporting (recommended)

Pass usageReporting to createToolHandler and it runs the reporter at the very end of the lifecycle, awaited before the response returns (bounded by timeoutMs, default 5s) so it completes even on serverless runtimes that freeze on response flush. Failures are logged, never fatal. No walletClient is needed server-side:

• Paid x402 calls → verification_type: "x402_settlement" with the payer address and settlement tx hash. The backend verifies the tx directly.
• EIP-3009-authenticated calls (behind predicateGate) → verification_type: "eip3009_authorization", forwarding the caller's original signed authorization. The caller already signed it to authenticate, so the reported identity is the real caller.

import { createToolHandler } from "@opensea/tool-sdk"

export const toolHandler = createToolHandler({
  manifest,
  inputSchema: InputSchema,
  outputSchema: OutputSchema,
  gates: [/* x402 paywall and/or predicateGate */],
  usageReporting: {
    chainId: 8453,                // EIP-712 USDC domain / x402 chain_id fallback
    toolChainId: 8453,            // ERC-8257: chain where the tool is registered
    toolRegistryAddress: "0x...", // ERC-8257: registry contract
    toolOnchainId: 42,            // ERC-8257: tool ID in the registry
    apiKey: process.env.OPENSEA_API_KEY!,
    // optional: aggregatorUrl, tokenAddress, timeoutMs
  },
  handler: async (input) => {
    return { result: `Processed: ${input.query}` }
  },
})

Reporting is always the service's responsibility (authenticated by apiKey), never the caller's; there is no caller self-reporting path. To report from a custom pipeline instead of the handler, use the standalone createEip3009UsageReporter / createX402UsageReporter (see the tool-sdk README "Usage Reporting" section).

onInvocation callback

You can also provide a custom onInvocation callback for bespoke analytics. It fires after the handler succeeds and settles, before the response is returned, with an InvocationEvent containing caller identity, payment status, and timing:

import { createToolHandler } from "@opensea/tool-sdk"
import type { InvocationEvent } from "@opensea/tool-sdk"

export const toolHandler = createToolHandler({
  manifest,
  inputSchema: InputSchema,
  outputSchema: OutputSchema,
  onInvocation: (event: InvocationEvent) => {
    // event.callerAddress — verified caller wallet
    // event.paid          — whether x402 payment settled
    // event.toolName      — resolved tool name from manifest
    // event.latencyMs     — handler execution time
    // event.timestamp     — invocation timestamp
  },
  handler: async (input) => {
    return { result: `Processed: ${input.query}` }
  },
})

8. End-to-End Examples

Example A: Free open-access tool

# 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"}'

Example B: x402 paid tool (pay-per-call only, no identity check)

# 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"}'

Example C: NFT-gated tool (identity check, no payment)

# Register with ERC721OwnerPredicate
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 0xYOUR_COLLECTION_ADDRESS

# Configure which collection(s) gate the tool (if not using --nft-gate):
npx @opensea/tool-sdk set-collections <TOOL_ID> 0xYOUR_COLLECTION_ADDRESS \
  --network base

# 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"}'

Example D: Subscription-gated tool

# Register with SubscriptionPredicate and configure in one shot:
PRIVATE_KEY=0x... npx @opensea/tool-sdk register \
  --metadata https://my-tool.vercel.app/.well-known/ai-tool/my-tool.json \
  --access-predicate 0xCBe0cd9B1d99d95Baa9c58f2767246C52e461f25 \
  --predicate-config '{"collection":"0xYOUR_SUBSCRIPTION_NFT","minTier":0}' \
  --network base

# Or configure after registration:
npx @opensea/tool-sdk configure-subscription <TOOL_ID> 0xYOUR_SUBSCRIPTION_NFT \
  --min-tier 0 --network base

# 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"}'

Example E: ERC-20 balance-gated tool

# Register with ERC20BalancePredicate and configure in one shot:
PRIVATE_KEY=0x... npx @opensea/tool-sdk register \
  --metadata https://my-tool.vercel.app/.well-known/ai-tool/my-tool.json \
  --network base \
  --erc20-gate 0xTOKEN_ADDRESS --erc20-min-balance 1000000000000000000

# Or configure after registration:
npx @opensea/tool-sdk configure-erc20-gate <TOOL_ID> 0xTOKEN_ADDRESS 1000000000000000000 \
  --network base

# 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"}'

Example F: NFT-gated + paid tool (combined gate, single round trip)

# Server: use paidPredicateGate (see references/predicate-gating.md)
# Single 402: identity proof + payment in one X-Payment signature
PRIVATE_KEY=0x... RPC_URL=https://mainnet.base.org \
  npx @opensea/tool-sdk pay \
  https://my-tool.vercel.app/api \
  --body '{"query": "hello"}'

References

• references/x402.md: pay-per-call protocol, server-side paywall, paidFetch
• references/predicate-gating.md: 402-based predicate access control (zero-value X-Payment), combined gates
• references/known-predicates.md: deployed predicate contracts and SDK helpers
• Tool SDK GitHub