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

The annotations already establish that this is read-only, idempotent, non-destructive, and closed-world. The description adds valuable behavioral context beyond the annotations: it lays out generations and complex family structures without overlaps, returns a zoomable chart, PDF posters, SVG, and GEDCOM, and instructs calling once rather than inventing relatives or dates.

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 dense but front-loaded: the first sentence establishes the chart-generation intent with useful synonyms, then moves to input modeling, outputs, and exclusions. Every sentence contributes either discoverability, usage routing, or behavioral transparency.

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?

Given a complex six-parameter tool with nested `people` data, annotations, and an output schema, the description is complete enough for correct invocation. It covers when to use it, how to shape the input, what it returns, and what it must not do; only sibling routing to `find_relationship` is not explicit.

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 the schema already documents all six parameters thoroughly. The description adds useful modeling guidance by telling the agent to convert the user's description into `people` entries with id, name, born, died, sex, parents, and spouses, and to make a single call, which goes beyond the structured 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 states a specific verb and resource: generating a family tree or genealogy chart from described relatives. It clearly distinguishes this from research, GEDCOM import, and organization/flowchart tools, but it does not explicitly name the sibling `find_relationship` as an alternative.

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?

It gives a clear trigger: use when the user wants a family tree, pedigree, descendant, hourglass, fan chart, or printable poster/template. It also gives exclusions such as not researching ancestors, importing GEDCOM, inventing relatives, or making organization charts, though it stops short of naming `find_relationship` as the alternative for relationship questions.

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