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

Annotations already declare readOnlyHint and openWorldHint, yet the description still adds real operational context: a 0.005 USDC x402 charge, an optional 1024-call free trial per IP per UTC day, and the fact that HTTP and MCP share one bucket. That pricing and rate-limit disclosure is exactly the kind of behavior an agent cannot get from annotations or schema.

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

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

It is a single front-loaded sentence that leads with the capability and then the cost model, then the returned facts. It is dense but nearly every clause carries information; the 'Not investment advice' disclaimer is the one element of arguable padding.

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

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

There is no output schema, so the description must carry the return-value burden, and it does by listing the concrete facts returned. What remains thin is error behavior for an address that is not a contract and the meaning of the non-defaulted network value, both of which matter for correct invocation.

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

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

Schema coverage is 50%: 'address' is documented in the schema while 'network' (enum base/base-sepolia, default base) is not described anywhere. The description adds only marginal meaning, hinting that the address may be either a token or a bare contract (the 'is contract' fact), but it never explains the network parameter or its default.

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

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

The description names a specific resource (a token/contract address) and enumerates exactly what is returned: contract status, ERC-20 metadata, total supply, owner, paused, EIP-1967 proxy/admin, balances and fact flags. This is far more specific than the name 'token_check', though it does not explicitly contrast itself with the sibling x402_precheck.

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

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

Usage is implied rather than stated: it is a 'quick check' of on-chain facts, and the 'on-chain facts only' phrasing signals that off-chain or market data is out of scope. There is no explicit when-to-use/when-not-to-use guidance relative to x402_precheck or web_to_markdown, and no prerequisite or failure guidance.

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