Name Whisper — Developer Documentation

Getting Started

Quick Start

Connect to the Name Whisper MCP server in under a minute. Choose HTTP for remote agents or stdio for local development.

Remote

HTTP Transport

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StreamableHTTPClientTransport } from
  "@modelcontextprotocol/sdk/client/streamableHttp.js";

const transport = new StreamableHTTPClientTransport({
  url: "https://namewhisper.ai/mcp",
});

const client = new Client({
  name: "my-agent",
  version: "1.0.0",
});

await client.connect(transport);

// Call a tool
const result = await client.callTool({
  name: "search_ens_names",
  arguments: { query: "3-letter words under 0.1 ETH" },
});

Stateful sessions with 30-minute idle timeout. No API key required.

Local

stdio Transport

// Claude Desktop / Cursor config
{
  "mcpServers": {
    "name-whisper": {
      "command": "node",
      "args": ["mcp-server.js"],
      "cwd": "/path/to/nw-terminal",
      "env": {
        "SUPABASE_URL": "...",
        "SUPABASE_KEY": "..."
      }
    }
  }
}

Requires the repository cloned with npm install and environment variables configured.

Tool Reference

All 34 tools

Each tool accepts JSON parameters and returns { content: [{ type: "text", text: "..." }] }. Click a tool to see parameters and examples.

Discovery Read-Only 4 tools

search_ens_names Natural language search across 3.6M names

Automatic intent detection routes to filtered DB search, semantic vector search, creative AI generation, or bulk availability check.

Param	Type		Description
query	string	required	Natural language query

Example

{ "query": "ocean themed names under 0.5 ETH" }

get_name_details Full metadata + listings + ENSIP-25 agent bindings

Owner, expiry, tags, active listings with prices, active offers, and agent identity text records.

Param	Type		Description
name	string	required	ENS name or label (e.g. "vitalik.eth")

Example

{ "name": "vitalik.eth" }

check_availability Bulk verify registration status

Returns status (AVAILABLE, REGISTERED, EXPIRED, INVALID), owner, expiry, and registration cost for each name.

Param	Type		Description
names	string[]	required	Array of ENS names or labels

Example

{ "names": ["coffee.eth", "tea.eth", "pixel.eth"] }

get_similar_names Semantic vector search for related names

256-dimensional vector embeddings across 3.6M+ names. Returns similarity scores and live marketplace data.

Param	Type		Description
name	string	required	ENS name or label
limit	number	default: 20	Max results (max 50)

Example

{ "name": "coffee", "limit": 10 }

Intelligence Read-Only 4 tools

get_valuation Three-track valuation with confidence rating

Track A: comparable sales with IQR outlier removal. Track B: quality-reference from word frequency + entity fame + search interest. Track C: self-history. Final = max(A, B, C).

Param	Type		Description
name	string	required	ENS name or label to value

Example

{ "name": "bitcoin.eth" }

get_market_activity Recent sales, listings, offers, transfers

Param	Type		Description
eventTypes	string[]	default: all	SALE, LISTING_CREATED, OFFER_CREATED, MINT, TRANSFER, RENEWAL, BURN
limit	number	default: 25	Max results (max 100)
offset	number	default: 0	Pagination offset

Example

{ "eventTypes": ["SALE"], "limit": 10 }

get_wallet_portfolio All ENS names owned by a wallet

Param	Type		Description
wallet	string	required	Wallet address (0x...) or ENS name
limit	number	default: 100	Max results (max 200)
offset	number	default: 0	Pagination offset

Example

{ "wallet": "vitalik.eth" }

find_alpha Discover underpriced listings

Scan for names listed below their comparable-sales valuation. Returns ranked opportunities with discount percentage and confidence.

Param	Type		Description
maxPriceEth	number	no cap	Max listing price in ETH
minDiscountPct	number	default: 20	Min discount vs estimated value (1-99)
minLength	number	optional	Min label length
maxLength	number	optional	Max label length
tags	string[]	optional	LETTERS_ONLY, NUMBERS_ONLY, EMOJI, PALINDROME
minConfidence	enum	default: LOW	HIGH (20+ sales), MEDIUM (10+), LOW (3+)
limit	number	default: 25	Max results (max 100)

Example

{ "maxPriceEth": 0.5, "minDiscountPct": 30, "limit": 10 }

Commerce Transaction 4 tools

purchase_name Register available or buy listed names

Auto-detects available vs listed. Available: returns registration recipe (commit → wait 60s → register). Listed: searches all marketplaces for best price, returns Seaport order data.

Param	Type		Description
name	string	required	ENS name to purchase
walletAddress	string	required	Buyer wallet address
maxPriceEth	number	optional	Max price (for listed names)
durationYears	number	default: 1	Registration duration
action	enum	default: auto	buy_listing, register, or auto

make_offer Submit a bid on a registered name

Param	Type		Description
name	string	required	ENS name to bid on
amountEth	number	required	Offer amount in ETH
walletAddress	string	required	Your wallet address
currency	enum	default: WETH	WETH, USDC, or DAI
expiryHours	number	default: 72	Offer expiry in hours

bulk_register Batch register up to 20 names in 2 txns

All names batched into a single batchCommit + batchRegister via Multicall3. Each name gets its own front-running protection secret.

Param	Type		Description
names	string[]	required	Array of ENS names (max 20)
walletAddress	string	required	Owner wallet address
durationYears	number	default: 1	Duration (same for all)

bulk_set_records Batch set records across up to 50 names

All record updates batched into one resolver.multicall() call. Supports addresses, texts, contentHash, and ENSIP-25 agent-registration.

Param	Type		Description
nameRecords	object[]	required	Array of { name, records } pairs (max 50)
walletAddress	string	required	Owner wallet address

Management Transaction 6 tools

set_ens_records Set resolver records (addresses, texts, content hash)

Multiple records batched into a single multicall transaction. Supports ENSIP-25 agent-registration via agentRegistration shorthand.

Param	Type		Description
name	string	required	ENS name to configure
records	object	required	{ addresses, texts, contentHash, agentRegistration }
walletAddress	string	required	Owner wallet address

Example

{
  "name": "myagent.eth",
  "records": {
    "texts": { "ai.agent": "true", "ai.capabilities": "trading" },
    "agentRegistration": { "registryAddress": "0xABC...", "agentId": "42" }
  },
  "walletAddress": "0x1234..."
}

renew_ens_name Renew single or batch names (Multicall3)

No commit/reveal needed. Any duration (no minimum). Anyone can renew any name. Batch renewals bundled into a single Multicall3 transaction.

Param	Type		Description
names	string \| string[]	required	Name or array of names
duration	number	default: 365	Duration in days

transfer_ens_name Transfer ownership (wrapped + unwrapped)

Auto-detects wrapped (ERC-1155) vs unwrapped (ERC-721). Resolver records are NOT affected by transfer.

Param	Type		Description
name	string	required	ENS name to transfer
fromAddress	string	required	Current owner (must sign)
toAddress	string	required	Recipient wallet

bulk_transfer_ens_names Batch transfer up to 20 names in 1 txn

Transfer multiple ENS names in a single Multicall3 transaction. Each name can go to a different recipient. Auto-detects wrapped (ERC-1155) vs unwrapped (ERC-721) per name.

Param	Type		Description
transfers	array	required	Array of { name, toAddress } pairs. Max 20.
fromAddress	string	required	Current owner of all names (must sign)

set_primary_name Set reverse resolution (primary name)

Controls what name displays when someone looks up your address. Name's ETH record must point to the wallet. One primary per address.

Param	Type		Description
name	string	required	ENS name to set as primary
walletAddress	string	required	Wallet address (must sign)

set_resolver Change resolver contract

Pass "public" to use the ENS Public Resolver. Records on the old resolver won't be visible after switching.

Param	Type		Description
name	string	required	ENS name
resolver	string	required	Resolver address or "public"

manage_ens_name Status check with recommendations

Returns registration status, expiry, wrapper state, owner, renewal pricing, and recommended actions. Use before any management operation.

Param	Type		Description
name	string	required	ENS name to check
includeRenewalPricing	boolean	default: true	Include on-chain pricing

NameWrapper Transaction 5 tools

wrap_name Wrap name into NameWrapper (ERC-1155)

ERC-721 → ERC-1155. Enables fuse permissions and protected subnames. Returns two-step recipe: approve + wrap.

Param	Type		Description
name	string	required	ENS name to wrap
owner	string	required	Current owner address
fuses	string[]	optional	Fuses to burn on wrap (irreversible)

unwrap_name Unwrap back to BaseRegistrar (ERC-721)

Clears all fuses. Fails if CANNOT_UNWRAP has been burned.

Param	Type		Description
name	string	required	ENS name to unwrap
owner	string	required	Current wrapped owner

manage_fuses Read/burn fuses on wrapped names

Three modes: read (check current), burn_owner_fuses, burn_child_fuses. All burning is irreversible. Fuses expire when the name expires.

Param	Type		Description
name	string	required	ENS name
action	enum	default: read	read, burn_owner_fuses, burn_child_fuses
fuses	string[]	conditional	Required for burn actions
expiry	number	optional	Unix timestamp (burn_child_fuses only)

mint_subnames Bulk create subnames for agent fleets

Each subname gets its own owner and records. Free to create — only gas costs. Designed for agent001.company.eth style fleet deployment.

Param	Type		Description
parentName	string	required	Parent ENS name
subnames	object[]	required	Array of { label, owner?, records? }
walletAddress	string	required	Parent name owner

extend_subname_expiry Extend subname expiry

Cannot exceed parent expiry. Parent owner can always extend; subname owner can only if CAN_EXTEND_EXPIRY fuse is burned.

Param	Type		Description
name	string	required	Full subname (e.g. "sub.coffee.eth")
years	number	default: 1	Years to extend (1-10)

Access & Recovery Transaction 2 tools

approve_operator Approve/revoke operator for ENS contracts

setApprovalForAll — covers ALL tokens on the specified contract. Use before wrapping, marketplace trading, or batch operations.

Param	Type		Description
owner	string	required	Address granting approval
operator	string	required	Address being approved
contract	enum	required	base_registrar, name_wrapper, or ens_registry
approved	boolean	default: true	true to approve, false to revoke

reclaim_name Reclaim ENS Registry ownership

Syncs the ENS Registry owner to match the BaseRegistrar token owner. Used when ownership is out of sync after direct token transfers.

Param	Type		Description
name	string	required	ENS name to reclaim
owner	string	required	Address (must own BaseRegistrar token)

Agent Identity Read + Write 5 tools

get_caller_identity Resolve authenticated agent identity via ERC-8128

Returns the identity of an ERC-8128 authenticated agent: wallet address, primary ENS name, text records, ENSIP-25 status, and portfolio summary. Call this first to confirm your identity is recognised.

Param	Type		Description
No parameters — identity is derived from the ERC-8128 signed request

provision_agent_identity One-call agent identity setup with ENSIP-25

Describe your agent's purpose and budget → get name recommendations with registration recipes, suggested ENS records, and ENSIP-25 agent-registration binding.

Param	Type		Description
purpose	string	required	What the agent does
walletAddress	string	required	Agent wallet address
budgetEth	number	default: 0.1	Max budget in ETH
preferences	object	optional	{ maxLength, style, mustInclude }
agentRegistry	object	optional	ENSIP-25: { registryAddress, agentId, chainId? }

Example

{
  "purpose": "DeFi trading bot",
  "walletAddress": "0x1234...",
  "budgetEth": 5.0,
  "preferences": { "style": "technical" }
}

get_agent_reputation Check agent credentials via ENSIP-25 + ERC-8004

ENSIP-25 verification is live: reads agent-registration text records. ERC-8004 reputation data is live on mainnet via the IdentityRegistry contract. Browse the agent registry →

Param	Type		Description
nameOrWallet	string	required	ENS name or wallet address

search_agent_directory Search registered AI agents via ERC-8004 registry

Queries the ERC-8004 IdentityRegistry on mainnet via 8004scan. Search by keyword, filter by capabilities or minimum reputation score. Returns on-chain agent profiles with ENS names and metadata.

Param	Type		Description
query	string	optional	Search query
capabilities	string[]	optional	Filter by capabilities
minReputation	number	optional	Minimum score (0-100)
limit	number	default: 25	Max results

search_knowledge Search ENS governance + protocol knowledge base

Governance proposals, protocol docs, developer insights, blog posts, forum discussions, and Farcaster casts from key ENS figures.

Param	Type		Description
query	string	required	What you want to know about ENS
source	enum	default: all	ens-forum, vitalik-blog, ens-blog, ens-docs, farcaster
limit	number	default: 6	Number of results

Internal Session 1 tool

get_usage_stats Session tool call counts, success rates, latency

No parameters. Returns per-tool call counts, success rates, and average latency for the current MCP session.

REST API

60+ HTTP endpoints

In addition to MCP tools, Name Whisper exposes a full REST API at https://namewhisper.ai/api/. All responses are JSON. Authenticated routes require a Bearer token from /api/auth/connect.

Authentication Public 3 endpoints

POST /api/auth/connect Wallet connection (returns JWT)

Simple address-based authentication. Send a wallet address, receive a JWT token for authenticated routes. No signature required.

Request

{ "address": "0x1234..." }

Response

{ "token": "eyJ...", "user": { "address": "0x1234..." } }

Use the token in subsequent requests:
Authorization: Bearer <token>

GET /api/auth/nonce Generate SIWE nonce

Generate a nonce for Sign-In with Ethereum (EIP-4361) authentication flow.

POST /api/auth/signin SIWE signature verification

Verify a SIWE message + signature. Returns JWT token on success.

Param	Type		Description
message	string	required	SIWE message string
signature	string	required	Wallet signature of the message

Search & Discovery Public 2 endpoints

POST /api/search LLM-powered semantic search

Natural language search with automatic intent detection. Routes to filtered DB search, semantic vector search, creative AI generation, or bulk availability check. Returns a searchId for async summary retrieval.

Param	Type		Description
query	string	required	Natural language search query
mode	string	optional	"create" for creative name generation

Example

POST /api/search
{ "query": "3-letter words under 0.1 ETH" }

GET /api/summary/:searchId Async AI search summary

Retrieve the AI-generated summary for a previous search. Generated asynchronously after search completes.

Name Profiles Public 5 endpoints

GET /api/name-profile/:label Comprehensive name profile

Registration info, transfer history, sales history, ownership, social scores, avatar, website, ENS records, holder intelligence (ETH balance, wallet age, ENS count). Aggregates data from ENS Subgraph, Etherscan, Web3.bio, and Alchemy.

GET /api/name-profile/:label/market Live marketplace data for a name

Current listings and offers across all marketplaces, aggregated and filtered by current owner.

GET /api/name/:label/records On-chain resolver records

Address records, text records (avatar, description, socials, AI metadata), and contenthash read directly from the on-chain resolver.

POST /api/name/:label/build-record-tx Build record update transaction

Returns encoded transaction calldata to update resolver records. Sign and broadcast with your wallet.

GET /api/wallet/:address/names All names owned by an address

Deduplicated list of ENS names owned or registered by a wallet address.

Market Intelligence Public 4 endpoints

GET /api/market-stats Global market overview

Sales counts, volume (24h & 7d), floor prices by category (3L, 4L, 5L, 999, 100K), top sale, trending categories, 24h floor deltas. Cached 5 minutes.

GET /api/protocol-analytics Protocol-wide analytics

Total registrations, renewal counts, historical trends. Auto-refreshes every 24h, persisted to disk.

GET /api/recent-sales Recent name sales

Filterable by category, price, and event type.

Query Param	Type		Description
days	number	default: 7	Lookback period (max 90)
minPrice	number	optional	Minimum sale price in ETH
category	string	optional	Filter by category

GET /api/recent-sales/:label Sales history for a specific name

Last 20 sales for a specific ENS name.

Categories & Collections Public 4 endpoints

GET /api/categories All categories with 7-day stats

Sales, volume, avg price, floor, ceiling per category. Includes Grails club mappings. Cached 5 minutes.

GET /api/categories/:slug Category detail with trends

Member list, Grails data, 7d/30d trends, badges.

GET /api/categories/:slug/ai-report AI-generated category analysis

AI analysis of category trends, market health, and opportunities.

GET /api/collections All collections

Complete list of ENS name collections with metadata.

Expiry Calendar Public 2 endpoints

GET /api/expiry-calendar Upcoming name expirations

Query Param	Type		Description
days	number	default: 30	Days ahead (max 90)
minLength	number	optional	Minimum label length
maxLength	number	optional	Maximum label length
charType	string	optional	Character type filter
dictionary	boolean	optional	Dictionary words only
status	string	optional	active, grace, premium
sort	string	optional	expiry, value, length
limit	number	default: 50	Max results (max 500)

GET /api/expiry-summary Expiry rollup by date range

High-level summary of upcoming expirations grouped by date range.

Whale Analytics Public 4 endpoints

GET /api/whales/addresses Top whale addresses

Query Param	Type		Description
days	number	default: 7	Lookback period (max 90)

GET /api/whales Whale leaderboard

Ranking, purchase count, total spent, average price. Includes ENS name resolution.

GET /api/whale/:address Individual whale detail

Purchase history, portfolio size, ENS names owned, total spent.

GET /api/sellers Top sellers in a period

Query Param	Type		Description
days	number	default: 7	Lookback period (max 90)
limit	number	default: 20	Max results (max 50)

Category Statistics Public 2 endpoints

GET /api/category-stats Sales stats by name length

Sale count, volume, avg/median/floor/ceiling prices for 3L, 4L, 5L, etc. Cached 5 minutes.

GET /api/category-trends Time-series category trends

Daily breakdown of sales trends per category. Cached 10 minutes.

Query Param	Type		Description
days	number	default: 7	Lookback period (max 90)
length	number	optional	Filter to specific label length

Trading Auth Required 17 endpoints

GET /api/trade/listings/:label Current listings for a name

Aggregated marketplace listings. Public, no auth required.

GET /api/trade/offers/:label Current offers on a name

All active offers. Public, no auth required.

GET /api/trade/market-data/:label Combined listings + offers

One-call aggregation of all marketplace data for a name.

GET /api/trade/availability/:label Registration availability + pricing

Check if a name is available for registration and get pricing tiers.

GET /api/trade/name-status/:label On-chain name status

Available, registered, premium auction, grace period, etc.

GET /api/trade/expiry/:label Expiry date + premium price

Days remaining, expiry timestamp, premium price if applicable.

GET /api/trade/rent-price/:label NameWrapper rental pricing

ENS rental pricing tiers for wrapped domains.

POST /api/trade/register-recipe Build registration transaction

Returns complete registration recipe with contract, ABI, steps, and gas estimate. Requires auth.

POST /api/trade/renew-recipe Build renewal transaction

Returns transaction data to extend name registration. Requires auth.

POST /api/trade/batch-renew-recipe Batch renewal via Multicall3

Bundle multiple renewals into a single transaction. Requires auth.

POST /api/trade/transfer-recipe Build transfer transaction

Returns transaction data to transfer name ownership. Auto-detects wrapped vs unwrapped. Requires auth.

POST /api/trade/set-primary-name Set primary ENS name

Set reverse resolution for a wallet address. Requires auth.

POST /api/trade/set-records Update resolver records

Build a multicall transaction to set address records, text records, and contenthash. Requires auth.

POST /api/trade/fulfillment Execute purchase/offer

Fulfill a Seaport order (buy listing or accept offer). Requires auth.

POST /api/trade/create-offer Create a marketplace offer

Submit a bid on any registered name. Requires auth.

POST /api/trade/create-listing List a name for sale

Create a Seaport listing for a name you own. Requires auth.

DELETE /api/trade/order/:orderId Cancel an order

Cancel an active listing or offer. Requires auth.

User Management Auth Required 14 endpoints

GET /api/user/me Current user profile

Address, ENS name, email, settings.

Watchlist GET, POST, PATCH, DELETE /api/user/watchlist

CRUD operations for the user's watchlist. POST to add, GET to list, PATCH /:label to update notes/tags, DELETE /:label to remove.

Search History GET, DELETE /api/user/history

GET to retrieve search history, DELETE to clear it.

Portfolio 5 endpoints under /api/user/portfolio-*

GET /api/user/portfolio-history — Historical portfolio snapshots
POST /api/user/portfolio-snapshot — Create point-in-time snapshot
GET /api/user/portfolio-stats — Aggregate stats (total value, count, unrealized PnL)
GET /api/user/portfolio-pnl — Detailed P&L per name
GET /api/user/portfolio-realized — Realized gains/losses on sold names

Email PUT, DELETE /api/user/email

PUT to set email for alerts, DELETE to remove.

Terminal / Chat Auth Required 5 endpoints

POST /api/terminal/chat AI chat (SSE stream)

Multi-turn conversation with the Claude-powered ENS agent. Returns Server-Sent Events stream. Backed by RAG over the ENS knowledge base.

Sessions CRUD at /api/terminal/sessions

GET /api/terminal/sessions — List user's chat sessions
GET /api/terminal/sessions/:id — Fetch session messages
POST /api/terminal/sessions — Create new session
DELETE /api/terminal/sessions/:id — Delete session

Knowledge Public 1 endpoint

GET /api/knowledge-search Search ENS knowledge base

Governance proposals, protocol docs, developer insights, blog posts, forum discussions, and Farcaster casts from key ENS figures.

Query Param	Type		Description
q	string	required	Search query
source	string	optional	ens-forum, vitalik-blog, ens-blog, ens-docs, farcaster
limit	number	default: 6	Number of results

Media Public 1 endpoint

POST /api/upload-avatar Upload avatar to IPFS

Multipart upload. Accepts PNG, JPG, GIF, WebP, SVG (max 5 MB). Returns IPFS URI, gateway URL, and CID. Use the IPFS URI as the ENS avatar text record value.

Recipes

Common Workflows

Provision an agent identity

Call provision_agent_identity with purpose, budget, and wallet
Pick a name from the recommendations
Execute the registration recipe with your wallet (commit → wait 60s → register)
Call set_ens_records with the suggested records (ai.agent, ai.capabilities, etc.)
Call set_primary_name to set reverse resolution

Find and buy underpriced names

Call find_alpha with your price ceiling and minimum discount
For each opportunity, call get_valuation for deep analysis
Call purchase_name to get the Seaport fulfillment data
Sign and broadcast the transaction with your wallet

Deploy an agent fleet

Register the parent name: purchase_name with action "register"
Wrap it: wrap_name to enable subname features
Mint fleet subnames: mint_subnames (e.g. agent001.fleet.eth, agent002.fleet.eth)
Configure all at once: bulk_set_records with agent metadata per subname

Standards

Protocol Support

Name Whisper implements emerging standards for AI agent identity on Ethereum.

ENSIP-25

Agent-to-ENS binding protocol. Cryptographically links an ENS name to an on-chain agent registry entry via standardized text records. Supported in set_ens_records, bulk_set_records, provision_agent_identity, and get_agent_reputation.

Live

ERC-8004

Agent identity registry standard. On-chain agent registration, reputation scoring, and capability validation. Live on Ethereum mainnet since Jan 2026. View the live registry feed →

Live

Payments

Machine Payment Protocols

Name Whisper supports two machine-to-machine payment protocols for agent transactions. All tools are currently free — fee switches exist to activate either protocol later.

x402

HTTP-native payment protocol via Coinbase. USDC on Base (chain ID 8453). Payment challenges and receipts flow through HTTP 402 responses and headers. x402.org

Dormant

MPP

MCP-native payment protocol via Stripe/Tempo. pathUSD on Tempo network. Payment challenges, credentials, and receipts flow through JSON-RPC _meta fields in the MCP SDK transport. mpp.dev

Dormant

Tool Classification

27 tools are permanently free (search, valuation, portfolio, market data, knowledge). 4 transaction tools (purchase_name, make_offer, set_ens_records, mint_subnames) are wrapped with payment gating. When fees activate, these tools return a 402 challenge that the agent resolves via the active protocol.

Payment Discovery

Agents can query the payment discovery endpoint to check which protocols are available, which tools are free vs paid, and current pricing.

GET /mcp/payments Payment protocol discovery

Returns supported payment protocols, active protocol, and per-tool classification with current pricing.

Response

{
  "activeProtocol": null,
  "protocols": {
    "x402": {
      "supported": true,
      "enabled": false,
      "currency": "USDC",
      "network": "base",
      "chainId": 8453
    },
    "mpp": {
      "supported": true,
      "enabled": false,
      "currency": "pathUSD",
      "network": "tempo",
      "transport": "mcp-sdk"
    }
  },
  "tools": [
    { "name": "search_ens_names", "classification": "FREE", "requiresPayment": false },
    { "name": "purchase_name", "classification": "TRANSACTION", "requiresPayment": false, "currentPrice": "0" },
    // ... all 34 tools listed
  ]
}

Payment Flow

When fee switches are activated, transaction tools use this flow:

x402 (HTTP transport)

Agent calls a TRANSACTION tool via HTTP
Server responds with HTTP 402 + payment challenge (USDC amount, pay-to address)
Agent pays on Base, receives receipt
Agent retries the tool call with payment receipt in headers
Server verifies receipt and executes the tool

MPP (MCP SDK transport)

Agent calls a TRANSACTION tool via MCP SDK
Server returns an MCP error -32042 with payment challenge in _meta
Agent pays on Tempo (pathUSD), receives credential
Agent retries with payment credential in the _meta field
Server verifies credential and executes the tool

34 MCP tools for ENS