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

Annotations only declare readOnlyHint, so the description carries the real behavioral load and does so well: it discloses that limit caps the FILINGS read rather than the trades returned, exposes filings_matching and the truncated flag, and warns that returned_trades must never be quoted as a total. This is exactly the non-obvious context annotations cannot provide.

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?

Two front-loaded sentences with no filler; the resource and filtering come first, then the truncation caveat, and every clause carries information an agent needs.

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 supplies the return shape (one row per transaction with amount range and filing PDF) plus the truncation semantics, which is everything needed to call and interpret the tool correctly.

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%, so baseline would be 3, but the description adds genuine meaning beyond the schema: it redefines limit as a cap on filings read rather than rows returned, which directly corrects the schema's 'Max rows, 1-25' wording.

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 concrete resource (stock trades disclosed by members of Congress via House/Senate Periodic Transaction Reports) and the dimensions it can be sliced by. An agent can tell it apart from insider_trades conceptually, though the sibling is never 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?

Listing the filter dimensions (member, ticker, transaction type, date) implies the use cases, but there is no explicit 'use this instead of X' routing and no exclusions, even though insider_trades and get_politician sit in the sibling set.

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