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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the bar is lower. The description adds genuinely useful behavior beyond them: it discloses the payload shape (summary, outline, short excerpt, FAQs, cited sources) and crucially that only an excerpt is returned, with a link out to the full article on huisly.nl. It omits error behavior for a bad slug.

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: verb and resource first, then the returned fields, then the outbound link. Dense but every clause carries information; the enumerated return list is slightly heavy for one sentence but does not waste words.

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 describe the return value, and it does so adequately (summary, outline, excerpt, FAQs, sources, link). The main gap is the undocumented 'kind' parameter, which matters for a tool whose sole required input is a slug that could belong to either content type.

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 only 33% (only 'language' is documented in-schema). The description adds real meaning for the required 'slug' by tying it to search_guides, but says nothing about the 'kind' enum (blog vs moving_guide) or how it interacts with slug — an agent must guess whether kind is a disambiguator or a filter.

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 ('Get one Huisly guide by slug') and immediately names the sibling that produces the slug ('from search_guides'), so an agent can distinguish it from search_guides without opening either schema. The clause listing what is returned nails down scope.

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 parenthetical '(from search_guides)' encodes the intended workflow: search first, then fetch by slug. However, it never says when-not to use this tool, nor what happens if a slug is unknown or stale, so it falls short of explicit alternatives/exclusions.

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