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

Annotations already declare this a safe, non-destructive read (readOnlyHint=true, destructiveHint=false), so the description only needs to add beyond that. It does add useful shape: results are app-ranked and include badge plus follow status. It says nothing about result volume, pagination behavior beyond the cursor param, or rate limits, so it is helpful but not rich.

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 sentences, front-loaded with the core behavior and ending with the cross-reference to follow_user. Dense but well ordered. Slightly compressed phrasing ('ranked like the app') costs a little clarity for a modest length saving.

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 correctly takes on the return-value burden by describing badge and follow-status fields and app-like ranking. Combined with annotations covering safety and the cursor param implying pagination, an agent has enough to call this correctly. Only the explicit relationship to search_users is missing.

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 only 33% (just the cursor), so the description has to carry real weight. It does: the empty-query-means-everyone rule and the name/handle-match behavior define the most semantically ambiguous parameter (query). limit and cursor are self-explanatory from name/type and the schema's own cursor note, so the remaining gaps are minor.

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 (discover) and resource (people/users) and pins the semantics: empty query returns everyone, otherwise a name/handle match, ranked like the app. This is much clearer than a bare 'search'. It stops short of explicitly contrasting with the sibling search_users, leaving some ambiguity between the two.

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?

'everyone (empty query)' implies a browse use case and 'Use follow_user to follow' routes the follow action to the correct sibling, so there is real, if partial, guidance. However, it never states when to pick this over search_users, which is the most likely confusion given the sibling list. Usage is implied rather than defined.

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