Top movers

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description contributes the useful temporal constraint ('Today's'), meaning results are a fresh daily snapshot rather than historical. It does not disclose the market/exchange universe covered, how 'biggest' is measured (percent vs absolute change), or whether results are cached/delayed.

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 with no filler, and the three supported modes are stated up front. It is a noun fragment rather than a verb phrase, but nothing is redundant.

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?

An output schema exists, so return-shape explanation is not required, and annotations cover safety. However, for a market-screening tool the description leaves out material context an agent needs to call it correctly: the covered market/exchange, the ranking metric behind 'biggest', and the meaning/bounds of `limit`. Adequate but with clear gaps.

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 0%, so the description must carry the parameter burden, and it largely does not. It restates the three `kind` enum values that the schema already enumerates, adding no new meaning (e.g., whether gainers are ranked by percent or dollar change), and says nothing at all about `limit` — no default, maximum, or behavior when omitted.

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?

Names a specific resource (gainers, losers, most actively traded stocks) with an explicit 'Today's' scope, which is more precise than a generic 'market data' tool. It is distinguishable from siblings like get_price_history or get_stock, though it does not explicitly contrast itself with the nearby get_market_daily_summary or get_market_overview.

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 when-to-use or when-not-to-use guidance, and no alternative is named. An agent cannot tell from the description whether this is the right tool versus get_market_daily_summary or get_market_overview for a market-wide snapshot; only the 'Today's' wording hints at a daily-snapshot role.

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