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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered and the description does not contradict it. The description adds only that the profile is 'public' and the subject 'fictional', and says nothing about what happens with an unknown or malformed slug (error vs empty result).

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 the action, scope and lookup key in order and zero filler. Nothing in the sentence could be cut without losing information.

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 rich annotations and no output schema, the definition covers the essentials. The remaining gaps are minor: no statement of lookup-failure behavior and no indication of return shape, though the absence of an output schema lowers that expectation.

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?

The schema has one required parameter with 0% description coverage, so the description carries the burden; it does add meaning by specifying the slug is a 'catalogue slug' rather than a name or numeric ID, which is genuinely useful. However it gives no format, casing, or lookup-failure guidance 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?

The description states a specific verb and resource: 'Read one ... public profile', scoped to a single item via 'using its catalogue slug'. The word 'one' implicitly contrasts with the enumerate-style list_companions sibling, though it never names that sibling explicitly.

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: the mention of 'catalogue slug' hints that the caller must already have a slug, presumably obtained from list_companions, but there is no explicit when-to-use, when-not, or named alternative. An agent must infer the routing between this and list_companions or search_docs.

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