get_user_hovercard

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

With no annotations, the description carries full burden for behavioral disclosure. It explains the return format ('Returns a list of context messages'), provides examples, and clarifies the pairing requirement for optional parameters. It does not mention auth requirements or error cases, but for a read-only tool the disclosure is solid.

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?

The description is two sentences plus a docs link. It front-loads the core purpose and immediately explains optional behavior, with no wasted words. The structure is logical and easy to scan.

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 simple tool with three parameters and no output schema, the description covers purpose, optional usage, return type, and examples. A docs link provides further reference. It lacks explicit error handling notes, but that is not critical for this straightforward read operation.

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 100%, so baseline is 3. The description adds value by explaining that subject_type and subject_id together scope the context, reinforcing the pairing dependency and clarifying what constitutes a 'subject' (repository, issue, pull_request, organization). This goes slightly beyond the schema's individual field descriptions.

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 clearly states the tool's purpose: 'Get contextual information about a GitHub user (their "hovercard") as it would appear in the GitHub web UI.' It distinguishes itself from sibling tools like get_user_by_username by specifying it returns hovercard context messages, not basic profile data.

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 description gives clear context on how to optionally scope the hovercard using subject_type and subject_id, explicitly stating both are required when either is provided. It does not explicitly contrast with alternatives like get_user_by_username, but the unique purpose is evident, so it falls just short of a 5.

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