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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds value annotations do not carry: it discloses the payload content (Markdown body plus author, update date and sources), which matters because there is no output schema. It does not mention missing-slug behavior or article size limits.

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 tight sentence with the resource and return payload front-loaded; nothing is wasted. It is arguably over-terse — the guidance an agent needs is absent rather than the text being verbose.

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 two-parameter read-only tool with full schema coverage and rich annotations, the description covers the main gap (return payload). However, with no output schema and no usage routing, an agent still lacks guidance on when this tool is the right call versus search_guide.

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 description coverage is 100%, and the slug description already explains provenance ('Article slug from search_guide') and the locale enum is self-documenting with a default. The description adds nothing beyond the schema, so 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 names a specific resource ('one guide article') and its return format (Markdown), which together with the verb in the tool name clearly distinguishes it from the sibling search_guide. It stops short of an explicit verb+scope statement in prose, but an agent can identify the operation without opening the schema.

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?

There is no when-to-use guidance, no mention of when not to use it, and no prose pointing to search_guide as the discovery path — that linking only appears inside the slug parameter's schema description. The agent must infer that this is the fetch-by-slug follow-up to a search.

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