get_chart_movers

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds meaningful context beyond that: the 3+ place threshold defining a 'mover', the two-day comparison window, which chart/kind and country defaults apply, and the Pro plan requirement. This is useful behavioral detail layered on top of the annotations.

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?

Front-loaded with the core return value, then scoping and parameter guidance in tight sentences with no filler. It is slightly dense but every sentence carries information (mover types, threshold, genre override, plan gating). Minor density rather than waste.

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, the description does the work of explaining what comes back (buckets of risers/fallers, entrants, drop-outs with names, and both-day standings). It also covers the key defaulting behavior and plan gating. It is nearly complete; only explicit alternatives to sibling tools are absent.

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 description coverage is 100%, so all six parameters (days, kind, appId, genre, limit, country) are already documented in the schema with defaults and enums. The description only reinforces one parameter (genre overrides the default category) and the general category-default behavior. This matches the baseline of 3 when the schema carries the semantics.

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: it returns chart movers (risers/fallers, new entrants, drop-outs) for the app's own category chart, plus where the app and its rivals stood. This is far more specific than a generic 'get movers' and implicitly contrasts with market-wide siblings by scoping to the app's own category. It stops short of naming a sibling (e.g. market_movers) explicitly, so it is clear but not fully differentiated.

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 practical usage context: the category defaults to the app's chart record and you 'pass genre to look at another', and it flags that this is a 'Pro plan' feature. However, there is no explicit when-to-use vs when-not, and no named alternative such as market_movers or get_charts for a broader view. Usage is implied rather than directed.

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