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

Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds the behavioral scoping that the response is metadata only and excludes MDX body, which is useful. It does not detail response fields or not-found behavior, so the added context is moderate.

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?

A single, front-loaded sentence conveys the purpose and a key limitation without waste. The parenthetical is compact and prevents a likely mis-call for MDX content.

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 simple single-parameter read tool with comprehensive safety annotations, the description sufficiently covers what is returned (metadata) and what is not (MDX body). It lacks specifics about available metadata fields or error behavior, but the simplicity of the tool lowers the necessity for more.

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?

The schema fully describes the slug parameter with 100% coverage, so the description adds no new parameter semantics. It merely references the slug concept already captured in the schema. 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 clearly states the tool retrieves full post metadata by slug, which is a specific verb-resource pairing. The parenthetical exclusion of MDX body makes the scope precise and distinguishes it from content-serving routes and list_posts.

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 tool's usage is clear: use it to fetch post metadata by slug. It also provides an explicit when-not by stating MDX body is served by app routes, preventing misuse. However, it does not explicitly name alternative sibling tools such as list_posts.

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