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

Goes well beyond the annotations: discloses billing semantics ('one fixed hit only when data is newly acquired'), which statuses are free (my_data, unavailable, total_cost=0), the 'at most five relative rows in API acquisition order' cap, the data_acquisition_status values, and that there is no count_only quote here. This is exactly the side-effect context annotations cannot convey.

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?

Dense but every sentence earns its place — billing, identifiers, row cap, and chaining each add actionable information with no filler. It is a single long paragraph rather than clearly bulleted/segmented, which slightly hurts scannability but not substance.

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 and 0% parameter coverage, the description still covers what comes back (relative rows, RelatedPersonID format, data_acquisition_status), cost behavior, cardinality, and the chaining prerequisite. Nothing an agent needs to invoke it correctly 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 0%, so the description carries the full burden, and it does so well: person_id is explained via the PersonKey format with an example (p4290), and fields is explained with its default (Standard), the note that Standard/All return the same 13 ids, and that comma-separated ids from get_fields are accepted. Only minor gaps remain (no field id enumeration), so a 4 rather than a 5.

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 and resource ('Acquire or re-fetch billable relative data for one Person'), the identifier format (person_id / REST PersonKey, e.g. p4290), and the coverage scope (all 50 US states and DC). An agent can distinguish it from siblings like get_property_persons or get_person_phones without opening any schema.

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?

Provides an explicit 'Typical chain: get_property_persons → take PersonID from a row → get_person_relatives' plus a downstream pointer to get_person_phones and a caveat about get_person_emails. It does not state an explicit when-not-to-use or name a direct alternative tool for the same data, so it falls 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.