Polyform

crypto_balance

Read-only

Wallet balance (Base) — Native ETH + USDC balance for any address on Base mainnet. Source: public RPC. JSON. Price: $0.003 USDC (Base, via x402).

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_balance"
  }
}

Input Schema

Name	Required	Description	Default
`address`	Yes	0x wallet address

Schema Changelog

Changes observed during successful MCP inspections.

First observedSep 1, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already cover read-only and non-destructive behavior; the description adds useful behavioral context: source is a public RPC, response is JSON, and each call costs $0.003 USDC via x402. This goes beyond the structured annotations without contradicting them.

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

Conciseness5/5

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

Four short fragments, each carrying distinct information: function, network, asset scope, data source, output format, and price. It is front-loaded with the core purpose and contains no filler or repetition.

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 one-required-parameter read-only tool, the description is complete: it states what is returned, the network, the source, and the pricing. Without an output schema, the JSON note plus the balance composition is sufficient for an agent to invoke and interpret the tool.

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% and the schema says '0x wallet address', so the baseline is 3. The description adds meaning by specifying that any address on Base mainnet is valid and that the parameter is the wallet whose ETH/USDC balance is returned.

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

Purpose4/5

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

The description clearly states the tool returns Native ETH + USDC balance for a given address on Base mainnet. It lacks an explicit action verb, but 'balance for any address' plus the network specificity is unambiguous. The Base/ETH/USDC scope distinguishes it from crypto_gas, crypto_protocol, and crypto_token_report.

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

Usage Guidelines3/5

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

The description implies when to use it: any time a wallet balance on Base is needed. It does not explicitly name sibling alternatives or state conditions for choosing another crypto tool, so the when/when-not guidance is left to inference.

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

All Polyform tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?