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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description's word 'snapshot' adds a point-in-time behavioral context, but it does not disclose data freshness, latency, or any limitations. With annotations handling the safety profile, this is adequate but not rich.

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, front-loaded sentence that names the deliverable and enumerates the key metrics with no filler. Every phrase earns its place, and the structure is easy to parse quickly.

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?

With no parameters, high schema coverage, and an output schema present, the description gives an agent everything needed to understand what will be returned. The metric list is sufficiently complete for a no-argument market snapshot tool.

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 about input semantics. The baseline for zero-parameter tools is 4, and the description appropriately focuses on what the returned snapshot contains rather than parameter syntax.

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 clearly identifies the tool as a 'Global market snapshot' and names the exact metrics it returns: total market cap, BTC/ETH dominance, Fear & Greed index, and Altcoin Season index. This differentiates it from most siblings by content, though it does not explicitly contrast it with closely related tools like sentiment_fear_greed or market_quotes.

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?

The description explains what the tool provides but gives no guidance on when to choose it over the many sibling market and sentiment tools. No alternatives, exclusions, or conditions are stated, so the agent is left to infer usage from the phrase 'Global market snapshot.'

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