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

With no annotations provided, the description carries the full burden, and it does disclose two useful traits: the operation is read-only and the data returned is the public-facing view of a mentor. It says nothing about authentication requirements, rate limits, or what happens when the slug does not resolve, which are the remaining behavioral facts an agent would want before calling.

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?

Two short sentences, front-loaded with the verb and resource, followed by the field summary and the read-only note. Every clause carries information; nothing is redundant or padded.

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 read tool with no output schema, enumerating the returned fields in the description usefully compensates for the missing return definition. The only real gap is failure behavior for an invalid slug, which is minor at this complexity level.

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?

There is a single parameter and schema description coverage is 100%; the schema already explains that slug is the segment after /mentors/. The description's "by slug" restates this without adding new syntax or format detail, 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 states a specific verb and resource ("Fetch full public details for a single mentor") and enumerates the returned fields (bio, location, ratings, certifications, taught styles, canonical URL). It implicitly contrasts with the list-oriented sibling search_mentors via "single mentor by slug," but never names that alternative, so sibling differentiation is inferred rather than stated.

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?

Usage is only implied: an agent can infer this is the detail-lookup counterpart to search_mentors because of "single mentor by slug." There is no explicit when-to-use guidance, no guidance on obtaining a slug, and no stated exclusions or error conditions for an unknown slug.

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