market_get_gainers_losers

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds useful behavioral details beyond the annotations: it returns separate lists for gainers/losers, includes token symbol and price change percentage, and specifies the data source (DefiLlama).

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 description is a single, densely informative sentence. It front-loads the action and resource, then details the output structure without any filler or redundancy.

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?

For a simple read-only data retrieval tool with no output schema, the description adequately covers the return format and data source. It does not mention default values or edge cases, but the schema covers the period default, making the overall package sufficient.

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 input schema has 100% coverage with descriptive parameter names and enums for period. The description adds only minor context (e.g., 'specified time period') but does not meaningfully enrich parameter understanding beyond the schema.

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 retrieving top gaining and losing tokens over a specified time period from DefiLlama. It specifies the output as separate lists with token symbol and price change percentage, distinguishing it from sibling market tools.

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 clearly implies when to use this tool: when you need top gainers/losers over a time period. It does not explicitly mention alternatives or exclusions, but the context is unmistakable and avoids ambiguity.

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