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

Annotations already declare readOnlyHint=true, openWorldHint=false, idempotentHint=true, destructiveHint=false, so safety is covered. The description adds behavioral detail about the return structure, including `sectors`, `families`, `without_documents`, and aggregated fields like `instrument_kinds`, `sectors_classified`, and `topics`, which goes beyond the 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?

The description is dense but well-structured: it leads with the core purpose, then usage, then the return shape. While it packs many details, each sentence earns its place; it could be slightly trimmed but remains efficient.

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?

Given there is no output schema, the description thoroughly explains the return values, listing all top-level fields and their subfields, and even covers edge cases like families without documents. This makes it fully adequate for an agent to call and interpret the results.

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?

With 0% schema description coverage, the description fully compensates by explaining the `sector` parameter: '`sector` narrows to one group of families (e.g. 'ley', 'ejecutivo', 'control', 'local')' and that providing it adds extra fields (`publisher`, `stored`, `classified`, `kinds`). This gives meaning beyond the 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 description opens with a clear statement of what the tool provides ('What exists: every publisher (family) with how many documents it has and how many have text.') and explicitly differentiates it from siblings by stating it's used to learn valid family keys before filtering `search` or `documents`. This gives a specific verb+resource and distinguishes it from related 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 explicitly states when to call the tool: 'Call it to learn the valid `family` keys and the kinds each publisher prints before filtering `search` or `documents`, or to judge whether a missing answer means a gap in the corpus.' It also explains that `sector` narrows to a group, providing clear context for usage.

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