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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds valuable behavior beyond these: returns at most 10 results, empty list means no match, relevance ordering, language handling, caching, and the linkage to fetch. This contextual information helps the agent anticipate outcomes and error cases.

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?

The description is longer than average but every paragraph earns its place: core purpose, tool contract context, alternative routing, query semantics, and behavior. The primary search behavior is front-loaded in the first sentence. Slight redundancy exists between the schema and the Query line, but overall it is well organized and scannable.

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 description is complete for a search/catalog tool of this complexity. It covers what is searched, output shape and limits, relevance ordering, empty results semantics, query language details, read-only/idempotent behavior, and how to follow up with fetch. An output schema exists, so return values need no further explanation, and all necessary agent guidance is present.

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% and the schema already describes the query parameter as natural language/keywords with accents and case ignored. The description adds the meaningful extra detail that the query may be in Portuguese or English, which goes beyond the schema. This justifies a score above the baseline of 3.

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 and resource: 'Searches the IBGE catalog' and explicitly defines the output as 'up to 10 matching documents as { id, title, url }, ordered by relevance'. It also distinguishes itself from siblings by labeling itself a 'catalog index, not a data query', which disambiguates it from the data-returning ibge_* tools.

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?

The description gives explicit routing guidance: 'For direct questions and for data (values, series, rankings) prefer the ibge_* tools...' and 'Pass one of the returned ids to fetch to read the document.' It clearly states when to use this tool versus alternatives and names the relevant sibling tools.

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