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

No annotations exist, so the description carries the full behavioral burden, and it does disclose the important operational facts: payment of 0.005 USDC via x402 PAYMENT-SIGNATURE header or API-key auth, with auto-pay for x402-capable clients and free calls for API-key clients. It does not mention caching, rate limits, or freshness of the snapshot, which keeps it from a 5.

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?

The core purpose sentence is front-loaded and dense with useful specifics, followed by a bracketed access note that is short and operationally necessary. Two blocks, no filler, though the access note could be marginally tighter.

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 and no annotations, yet the description lists the returned metrics and covers authentication and cost, which is what an agent needs to call it correctly. Minor gaps remain around units/formatting of the returned figures and snapshot freshness.

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?

With zero parameters and a declared 100% schema coverage baseline, there is nothing to document; the description correctly implies a parameterless call. No misleading or missing parameter information.

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 and verb — 'Global crypto market snapshot' — and enumerates exactly what it returns: total market cap, BTC dominance, total 24h volume, and the 24h change. It also explicitly contrasts the scope against a 'per-asset reading,' letting an agent separate it from get_asset and get_market_data without inspecting schemas.

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?

It gives a clear use condition: 'when the user asks about overall market conditions or wants a macro view rather than a per-asset reading.' The contrast is conceptual rather than naming a specific sibling tool to use instead, so routing among the many market-data siblings still requires inference, but the guidance is solid.

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