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

With no annotations, the description carries the full burden. It does disclose a meaningful behavioral constraint — all figures are scoped to the last 90 days — but says nothing about whether the window is configurable, whether results are cached, or what the data source/freshness guarantees are.

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 with the resource named first and the returned metrics enumerated after — well front-loaded. The colon-separated metric list is a bit packed but every item is informative rather than filler.

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 no parameters, the description must convey what comes back, and it does by listing each aggregate. The main remaining gap is whether the 90-day window is fixed or adjustable and what the response shape looks like, but an agent can call this correctly with what is given.

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 disambiguate; the baseline of 4 applies. Nothing in the description conflicts with the empty input 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 verb 'Aggregate' is specific, and the description enumerates the exact statistics returned (trade/member/ticker totals, buy vs sell counts, latest dates, most-traded tickers). This makes it clearly distinguishable from get_congress_trades and get_congress_member in practice, though it never names those siblings 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 rather than stated: an agent can infer this is the summary/rollup endpoint versus the raw-listing siblings, but the description gives no explicit 'use this when you want an overview, use get_congress_trades for individual records' guidance.

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