get_ydna

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: it discloses the key output flag ('has_data is false when the person has no Y-DNA recorded, which is the normal case') and the interpretation limits of the data, which helps an agent avoid overclaiming a proven link.

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 purpose is front-loaded, which is good, but the definition runs to four short paragraphs for a two-parameter read-only getter. The middle paragraph on common paternal ancestors is genuinely interpretive but somewhat tangential to invoking the tool, and could be tightened.

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?

No output schema exists, so the description carries return-value burden, and it does explain the critical has_data field and the clade ordering. It does not fully describe the overall return structure (e.g., how the terminal haplogroup is presented), but for a read-only tool with a documented schema it is largely complete.

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%, and both parameters (person, include_raw) are fully documented in the schema, including the raw SNP string. The description adds nothing about parameter syntax or the meaning of include_raw, so it sits at the baseline 3 where the schema does the heavy lifting.

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: 'Report a person's Y-DNA haplogroup, from broadest clade to terminal.' It is clearly distinct from siblings like get_dna_matches and parse_dna_segments, which handle matches and segment parsing rather than a single person's haplogroup.

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 interpretive context (paternal-line-only scope, what a shared terminal clade implies) but never explicitly says when to use this tool versus get_dna_matches or other DNA tools. Usage is implied rather than stated, and the 'normal case' of has_data=false is a useful hint but not a routing rule.

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