get_facts

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

Beyond the readOnly/openWorld annotations, the description discloses real behavioral traits: living and private people are withheld unless include_private is set, and the call is slow because the server computes everything per call. These are genuine operational facts an agent needs and are not captured by 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?

Front-loaded with the core output definition, then one line each for scope, plausibility use, privacy behavior, and performance. No filler; every sentence carries distinct 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?

For a read-only tool with no output schema, it conveys the kind of results returned, the exclusion rule, and the performance cost. It lacks a full enumeration of all statistics produced and pagination/ranking return detail, but is otherwise sufficient to call correctly.

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 rank, person, person_filter, and include_private are already documented in the schema. The description restates the include_private exclusion behavior but adds no syntax or format meaning beyond what the schema provides, so the baseline 3 applies.

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 (read) and resource (the tree's record-holders) and enumerates concrete outputs — oldest at death, youngest parent, most children. The clause 'Superlatives across a set of people, not statistics about one person' crisply distinguishes it from single-person stat tools like db_stats or get_person.

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 a clear when-to-use scenario: an implausible holder signals a data error, making this a quick plausibility check. It does not name specific sibling alternatives (e.g. verify_tree, db_stats) or state when not to use it, so it stops short of full routing guidance.

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