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

Annotations already mark the tool as read-only, open-world, idempotent, and non-destructive. The description adds that it is read-only, requires no API key, and returns 'not found' for unknown IDs. It also details the response fields, providing valuable behavioral context beyond the annotations.

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 well-organized: it opens with the core function, lists fields, gives usage examples, explains prerequisites, and details parameters. Every sentence adds value. It could be slightly more concise, but it efficiently conveys all necessary 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?

The tool is simple (get profile by ID), and the description covers what it returns, how to obtain the ID, behavior on missing IDs, and authentication (none required). No output schema exists, but the description enumerates response fields. This is complete for an agent to use correctly without further guesswork.

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 description explains personId as 'a canonical person id such as 'vitalik-buterin'' and clarifies behavior on unknown IDs. For rationale, it provides examples and states the 20-500 character requirement. Schema coverage is 50% (only rationale described), but the description compensates by elaborating on both parameters, adding meaning beyond the schema.

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 it retrieves a person's profile by ID, lists the fields returned (name, bio, teams, positions, projects, accounts), and gives example queries. It distinguishes from siblings like search and resolveId by specifying that this tool requires an exact ID.

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 explicitly instructs to first find the personId using search or resolveId with type 'people', and notes that the tool needs an exact ID, not a name. It provides example use cases. However, it doesn't explicitly contrast with other sibling tools like getCoinById, which is acceptable given the domain difference.

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