Source Code

Zerion API Skill

Query web3 wallet data, token prices, NFTs, and transaction history via the Zerion MCP connector.

Authentication

Zerion API requires a key for every request. The key is not stored in the MCP connector settings — the user must provide it each chat session.

Workflow

At the start of any Zerion-related task, if no API key has been provided yet, ask: "To query Zerion, I'll need your API key. You can find it at https://dashboard.zerion.io/. Please paste it here."
Store the key in memory for the duration of the conversation. Never write it to files, display it in artifacts, or log it.
Pass the key to the MCP server or REST calls as described below.

Auth Format

Zerion uses HTTP Basic Auth: the API key is the username, password is empty.

Authorization: Basic <base64(API_KEY + ":")>

Example: key zk_dev_abc123 → base64 of zk_dev_abc123: → emtfZGV2X2FiYzEyMzo=

MCP Connection

The Zerion API MCP server is at https://developers.zerion.io/mcp.

When using MCP tools directly (outside artifacts), pass the API key as required by the tool parameters.

When building artifacts that call the Anthropic API with MCP, include the key in the inner prompt so the inner Claude can authenticate:

mcp_servers: [
  { type: "url", url: "https://developers.zerion.io/mcp", name: "zerion-mcp" }
]

Important: In artifacts, receive the API key as a prop or state variable — never hardcode it. Example pattern:

// User inputs key via a secure input field (type="password")
const [apiKey, setApiKey] = useState("");

// Pass key to inner Claude prompt so MCP calls authenticate
const prompt = `Using the Zerion API key: ${apiKey}, get portfolio for wallet 0x...`;

Quick Reference: Common Workflows

1. Wallet Portfolio Overview

Prompt the inner Claude to call the Zerion API for the wallet's portfolio:

Get the portfolio for wallet {address} in USD. Include total value, daily changes,
and distribution by chain and position type.

Endpoint: GET /v1/wallets/{address}/portfolio

currency: usd (default), eth, btc, eur, etc.
filter[positions]: only_simple (default), only_complex (DeFi), no_filter (all)

2. Wallet Token Positions

List all fungible positions for wallet {address}, sorted by value descending.

Endpoint: GET /v1/wallets/{address}/positions/

filter[positions]: only_simple | only_complex | no_filter
filter[chain_ids]: comma-separated chain IDs (e.g., ethereum,polygon)
filter[position_types]: wallet, deposit, staked, loan, locked, reward, investment
sort: -value (highest first) or value
filter[trash]: only_non_trash (default)

3. Transaction History

Get recent transactions for wallet {address}, filter for trades only.

Endpoint: GET /v1/wallets/{address}/transactions/

filter[operation_types]: trade, send, receive, deposit, withdraw, mint, burn, claim, approve, etc.
filter[chain_ids]: filter by chain
filter[min_mined_at] / filter[max_mined_at]: timestamp in milliseconds
page[size]: max 100

4. Profit & Loss (PnL)

Get PnL for wallet {address}. Show realized gain, unrealized gain, fees, and net invested.

Endpoint: GET /v1/wallets/{address}/pnl

Returns: realized_gain, unrealized_gain, total_fee, net_invested, received_external, sent_external
Uses FIFO method
filter[chain_ids], filter[fungible_ids]: narrow scope

5. Wallet Balance Chart

Get the balance chart for wallet {address} over the past month.

Endpoint: GET /v1/wallets/{address}/charts/{chart_period}

chart_period: hour, day, week, month, 3months, 6months, year, 5years, max
Returns array of [timestamp, balance] points

6. Token Price & Search

Search for the fungible asset "ethereum" and return its price and market data.

Endpoint: GET /v1/fungibles/

filter[search_query]: text search (e.g., "ethereum", "USDC")
sort: -market_data.market_cap, -market_data.price.last, etc.
Returns: name, symbol, price, market_cap, circulating_supply, changes (1d/30d/90d/365d)

7. Token Price Chart

Get the price chart for fungible {fungible_id} over the past week.

Endpoint: GET /v1/fungibles/{fungible_id}/charts/{chart_period}

Same chart periods as wallet charts
Returns [timestamp, price] points

8. NFT Positions

List all NFT positions for wallet {address}, sorted by floor price descending.

Endpoint: GET /v1/wallets/{address}/nft-positions/

sort: -floor_price, floor_price, created_at, -created_at
filter[chain_ids]: filter by chain
include: nfts, nft_collections, wallet_nft_collections for richer data

9. NFT Portfolio Value

Endpoint: GET /v1/wallets/{address}/nft-portfolio

Returns total NFT portfolio value

Building Artifacts with Zerion Data

When building React/HTML artifacts that display Zerion data:

Collect the API key securely via a type="password" input field
Never display or log the key in the UI
Pass it through the MCP prompt so the inner Claude can authenticate

// apiKey comes from a password input, never hardcoded
const response = await fetch("https://api.anthropic.com/v1/messages", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    model: "claude-sonnet-4-20250514",
    max_tokens: 1000,
    messages: [
      {
        role: "user",
        content: `Use the Zerion API with key "${apiKey}" to get the portfolio
                  overview for wallet ${walletAddress} in USD.
                  Return ONLY a JSON object with: totalValue, dailyChangePercent,
                  dailyChangeAbsolute, topChains (array of {chain, value}),
                  positionBreakdown (wallet, deposited, staked, borrowed, locked).`
      }
    ],
    mcp_servers: [
      { type: "url", url: "https://developers.zerion.io/mcp", name: "zerion-mcp" }
    ]
  })
});

Processing MCP Responses

MCP responses contain multiple content blocks. Extract data by type:

const data = await response.json();

// Get tool results (actual Zerion data)
const toolResults = data.content
  .filter(item => item.type === "mcp_tool_result")
  .map(item => item.content?.[0]?.text || "")
  .join("\n");

// Get Claude's text analysis
const textResponses = data.content
  .filter(item => item.type === "text")
  .map(item => item.text)
  .join("\n");

Key Notes

Address formats: Supports EVM addresses (0x...) and Solana addresses. ENS names may need resolution first.
Solana limitations: No protocol positions or NFT transactions for Solana addresses.
Currency options: usd, eth, btc, eur, krw, rub, gbp, aud, cad, inr, jpy, nzd, try, zar, cny, chf
Pagination: Use links.next from responses for pagination; never construct page[after] manually.
Rate limits: API returns 429 on throttling. Implement retry with backoff in artifacts.
Treat IDs as opaque strings: Never assume format of IDs; they may change.
DeFi positions: Use filter[positions]=no_filter to include protocol positions alongside wallet positions.
LP grouping: Liquidity pool positions share a group_id attribute — group by it to display pools correctly.

Detailed Endpoint Reference

For full parameter details, response schemas, and edge cases:

Wallet endpoints: See references/wallet-endpoints.md
Fungible & NFT endpoints: See references/fungible-nft-endpoints.md

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