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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description contributes beyond that by stating the payload is Markdown, which matters for rendering; it says nothing about size, failure modes, or whether guides are static.

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 compact sentence that front-loads the return format before the enumeration. No filler, though it opens as a fragment without a verb, which reads slightly clipped.

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 lookup with no output schema, the description covers the format and the full option space, which is what an agent needs to call it correctly. Missing only the explicit-purpose sentence and any note on guide size or staticness.

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 0%, but the enum values carry no self-explanatory meaning on their own, and the description supplies a human label for each of the seven slugs. That is real added meaning beyond the raw enum, though it stops short of saying when to prefer one guide over another.

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 fragment 'A guide as Markdown' names the resource and the return format, and the enumerated slugs make the topical scope concrete. The verb is only implied by the name/title rather than stated, and no sibling is named, but the guide-versus-icon distinction against the sibling set is obvious from the content list.

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 explicit when-to-use or when-not-to-use statement, and no alternative tools are referenced. Implicitly, the per-slug labels tell the agent which guide answers which kind of question, which is a usable but indirect selection aid.

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