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

No annotations are provided, so the description carries the full behavioral burden. It implies a read-only lookup but says nothing about what happens with an unknown/invalid slug, whether auth is required, or the shape/size of the returned detail, which for a 'full details' tool is a meaningful gap.

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 with zero filler; the resource and the key constraint (one stone, by slug) come first, and the provenance hint is appended compactly.

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, no-output-schema lookup tool the description covers the essentials (what it returns and where the slug comes from). It stops short of covering failure modes or expected return richness, which is adequate but not 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 description coverage is 0%, so the description must compensate for the single 'slug' parameter. It does add provenance value by tying the slug to search_stones, but it never clarifies format constraints (maxLength 120, string identifier) beyond that.

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 ('Full details for one stone by slug') and implicitly contrasts with the list-style sibling search_stones by specifying a single stone. It is clear what the tool returns, though it does not explicitly name the other siblings it is not.

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_stones)' implies the correct workflow — obtain a slug via search_stones, then fetch details here — which is useful routing context. However, it gives no explicit when-not guidance (e.g., use search_stones when you don't yet have a slug) and no mention of prerequisites or error behavior.

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