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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds that it returns 'top items with obligation amounts', which informs the agent of the output nature beyond just the schema. It does not contradict 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?

Three sentences with zero fluff. The primary purpose is stated first, followed by a usage hint, and a practical chaining example. Every sentence earns its place.

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?

The tool has an output schema and rich param schema. The description explains the return type (top items with obligation amounts) and gives a chaining workflow. It doesn't mention edge cases like empty results or specific filters, but these are covered by schema and are not critical for basic invocation.

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 parameters are documented in the schema. The description does not elaborate on parameter formats or constraints beyond what the schema provides. The only added value is the chaining hint, but that is not parameter-specific. 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?

The description states a specific verb ('Aggregate'), a resource ('federal spending'), and the grouping dimensions explicitly (NAICS, PSC, agency, CFDA, recipient). It clearly distinguishes this from sibling tools like search or time-series tools by focusing on category breakdowns.

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 states it is 'useful for trend and breakdown analysis' and gives a concrete chaining example (NAICS codes into usaspending_search_awards or autocomplete_filters). It doesn't explicitly contrast with spending_over_time or by_geography, but the category focus and chaining hint make when-to-use clear enough.

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