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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuinely new behavior: the response is Markdown with absolute links and also contains related posts, and the content is free/complete (no paywall truncation) — details an agent cannot get from 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?

Two compact sentences with the core behavior front-loaded: what is returned, in what format, plus what comes along with it. The trailing 'O blog é gratuito e sai completo' carries some informational value (no truncation/paywall) but edges toward promotional filler.

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 must characterize the return value, and it does: Markdown with absolute links plus related posts. What is missing is any note on locale behavior or what happens when a slug is not found, but for a two-parameter read tool this is largely complete.

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 50%: locale is documented in the schema, but slug has no schema description, and the description only restates that lookup is by slug without adding format, length, or slug-discovery guidance. The locale parameter is never mentioned, so the description does not fully compensate for the coverage gap.

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?

States a specific verb and resource ('Devolve um post do blog pelo slug') plus the return format, so an agent can tell this is single-article retrieval rather than a listing. It does not explicitly name the sibling it differs from (e.g. list_articles, search_library), so it stops short of a 5.

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 phrase 'pelo slug' implies the precondition that a known slug is required, which is useful context. However, there is no explicit when-to-use guidance, no mention of when to prefer search_library or list_articles instead, and no exclusion conditions.

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