get_user

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

With no annotations, the description carries the full burden and partially meets it: it discloses that only public profile data is returned and that library entries are gated by the target user's privacy setting, which is a real behavioral constraint an agent must anticipate. It stops short of stating auth requirements, rate limits, or failure behavior for an unresolved name.

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, no filler, front-loaded with the action and identifier options before the optional flag. Every clause carries information the agent needs.

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 usefully enumerates the return shape (bio, book/follower counts, privacy) and the conditional library payload. The one gap: six parameters with zero required means the agent must infer that at least one of id/username/name is necessary, and that constraint is not stated.

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 100%, so the baseline is 3. The description adds genuine meaning by tying include_library to the target's privacy setting and by framing id/username/name as alternative lookup keys rather than listing fields already documented.

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 ('look up') and resource ('another Hardcover user's public profile'), plus the three lookup keys (id, username, name). The word 'another' quietly distinguishes it from the sibling `me`, and the resource differs from `get_user_library`/`get_user_reviews`.

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?

Gives an explicit conditional for the main optional behavior: 'Set include_library=true to also fetch their recent library entries (subject to their privacy setting).' It does not, however, tell the agent when to prefer `get_user` over `get_user_library` or `me`, so it lacks true alternative routing.

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