SiteCheck Crypto & Finance

Token balances of an EVM wallet across chains

crypto_zapper_token_balances

Read-only

Token balances of an EVM wallet across chains from Blockscout explorers: native coin and ERC-20 holdings with amount, USD price and USD value (largest first), plus per-chain and overall USD totals. Ethereum, Optimism and Gnosis by default; Base, Arbitrum and Polygon when the operator's free Blockscout key is set. Prices are Blockscout's; airdropped tokens can be spam. Related tools on this server, for a different need: crypto_solana_token_extensions when you need Solana SPL mint audit from the chain: program, authorities; crypto_token_holder_concentration when you need Ethereum ERC-20 holder concentration from Blockscout: top. Price: $0.002 in USDC per successful call, paid with x402 (Base, Solana or Arc); failed calls are not charged.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "address": "<address>"
    },
    "name": "crypto_zapper_token_balances"
  }
}

Input Schema

Name	Required	Description
`limit`	No	Tokens per chain, 1 to 50 (default 20)
`chains`	No	Comma list from ethereum, optimism, gnosis, base, arbitrum, polygon (default: every chain available)
`address`	Yes	EVM wallet address (0x + 40 hex characters)

Output Schema

Name	Required	Description	Default
`chains`	No
`source`	No
`address`	No
`totalUsd`	No
`checkedAt`	No
`unavailableChains`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 23, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Adds substantial context beyond readOnlyHint/openWorldHint: the upstream data source (Blockscout), validity caveat that airdropped tokens may be spam, dependency on an operator key for extra chains, and the cost model ($0.002 USDC per successful call via x402 on Base/Solana/Arc, failures not charged). These are exactly the operational facts an agent needs before spending money on a call.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the purpose and keeps everything in a tight block with no filler sentences. The delivery is dense and semicolon-chained, making the cost and sibling-routing clauses easy to skim past, but nothing is genuinely redundant.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only, three-parameter, output-schema-backed tool, the description covers data source, return shape at a high level, chain defaults, data-quality caveat, and billing terms. An agent could decide whether to call it and predict the charge without consulting anything else.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: it specifies which chains are returned by default and under what condition the rest appear, refining the schema's vaguer 'default: every chain available'. It also states ordering (largest first), which frames how the limit parameter behaves per chain.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Token balances of an EVM wallet across chains from Blockscout explorers') and enumerates the payload: native coin and ERC-20 holdings with amount, USD price and USD value, plus per-chain and overall totals. It also explicitly separates itself from two siblings by naming the different need each serves.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear usage context: the default chain set (Ethereum, Optimism, Gnosis) and the condition that unlocks Base/Arbitrum/Polygon (operator's free Blockscout key must be set). Alternatives are named for adjacent needs, but portfolio-style siblings such as crypto_debank_wallet_portfolio and crypto_solscan_account_tokens are not mentioned, so the routing guidance is good rather than exhaustive.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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