add_dna_match

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

Annotations declare this is a non-read-only, non-destructive, non-idempotent write, so the safety profile is covered. The description adds genuinely useful behavior not in the annotations: atomic validation ('Nothing is written unless the segments parse'), the storage/interop guarantee that get_dna_matches will read it back, and the always-mint-a-new-citation semantics. It stops short of permissions, error modes, or return shape, so not a 5.

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?

Three short, front-loaded sentences: purpose first, then behavioral guarantee, then a scope caveat. Mostly waste-free, though the explanatory clause 'unreadable data would otherwise record a match sharing no DNA' is slightly verbose relative to the point it makes.

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 four-required-parameter write tool with no output schema and fully documented parameters, the description supplies the rationale, the atomicity guarantee, and the conceptual boundary against relationship recording – enough for correct invocation. A return-value or permission note would close the remaining gap, but nothing essential for calling 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 100% – the segments, citation, person, and match parameters are all richly documented in the schema itself, including the citation precedence rules and segment format. The description reinforces the citation semantics ('cited to the test that found it') but adds no syntax or format detail beyond the schema. Baseline 3 applies when 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 ('Record a DNA match as evidence, cited to the test that found it') and scopes it clearly against the read-side sibling by noting get_dna_matches reads the stored match back. An agent can distinguish this from get_dna_matches, parse_dna_segments, and get_ydna without opening a 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?

The description draws a useful boundary ('A match proves the two share DNA, not how they are related. Record any relationship separately'), which implies when this tool is and isn't the right one. However, it never names an alternative tool (e.g. parse_dna_segments for validating raw data) or states prerequisites beyond 'add them first if they are not in the tree' (which lives in the schema). Guidance is implied rather than explicit.

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