Top movers

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description earns credit for adding output semantics: percent_change is a fraction (0.05 = 5%) and results are ranked separately per direction. It still does not state data freshness/snapshot timing or pagination/truncation behavior.

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 dense sentence that front-loads the resource, then the returned fields, then the ranking rule. No filler; the parenthetical percent fraction clarification is the only elaboration and it is load-bearing.

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 output schema and only two optional params, the description usefully enumerates the returned fields (price, change, percent_change) and their units. Only minor gaps remain, such as the definition of 'today' (session vs calendar day) and result size interactions with 'top'.

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 100%: 'top' and 'market_type' are both fully documented in the schema. The description largely restates these ('ranked within each direction' mirrors the schema's 'how many gainers and how many losers'), so baseline 3 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?

States a specific verb+resource ('Today's top gainers and losers') and names the two supported market types. The price-change ranking metric is clearly distinct from the volume-based sibling 'market_most_active', though no sibling is named explicitly.

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 by 'Today's' (a same-day ranking screen) and by the stocks/crypto choice, but there is no explicit when-to-use, when-not-to-use, or pointer to alternatives such as market_most_active or market_snapshots.

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