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

Annotations already declare readOnly/idempotent/closed-world, and the description adds value beyond them: it discloses that no account is required and describes the exact return shape (Markdown body plus title, date, URL, related lessons), which matters since there is no output schema.

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?

Four tight sentences: return contents first, then the usage trigger, the fallback, and the citation requirement. No filler, and the most decision-relevant information (what you get, when to call) is front-loaded.

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?

For a one-parameter read tool with no output schema, the description covers inputs (slug provenance), outputs (article fields and lessons), auth ('no necesita cuenta'), and error recovery. Nothing needed to call it correctly is missing.

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 single slug parameter is already fully documented there, including the max length, the 'without /blog/' constraint, an example, and the fact it is returned by buscar/listar_articulos. The description only repeats the provenance, so it adds little 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 states a specific verb+resource (retrieve the full Markdown text of a blog article) and enumerates the payload (title, date, URL, related course lessons). It also distinguishes itself from siblings by noting the required slug comes from buscar or listar_articulos.

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 gives an explicit trigger ('cuando ya tienes el slug ... y necesitas el contenido para responder o resumir'), a fallback for the failure case ('Si el slug no existe, búscalo con buscar'), and an instruction to cite the article URL. Alternatives and conditions are fully spelled out.

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