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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. Beyond that, the description adds nothing: no indication of data freshness, snapshot timing, caching, or whether the response is a point-in-time aggregate versus a live figure. For a tool with zero parameters and an output schema, more behavioral context would have been easy and useful.

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?

A single short sentence with no filler, front-loaded with the provider and the subject. It is efficient but arguably under-specified rather than tight — the brevity is closer to omission than to discipline.

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?

Because an output schema exists, the return structure need not be explained. However, the description never states what the global snapshot covers (total market cap, volume, dominance, active coins) nor how it differs from coingecko_global_charts, leaving the agent with a real selection gap for a parameterless sibling-heavy toolset.

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?

The tool takes zero parameters, so there is nothing for the description to clarify beyond what the empty schema already conveys. Baseline of 4 applies.

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 phrase 'CoinGecko global market snapshot' names the resource (aggregate global crypto market data) but uses a vague verb ('snapshot') rather than stating what is retrieved. It does not distinguish itself from the nearby sibling coingecko_global_charts, which an agent could easily confuse it with.

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?

There is no guidance on when to call this versus coingecko_global_charts, coingecko_markets, or coingecko_gainers_losers. The agent is left to infer the use case entirely from the name.

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