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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description earns credit by adding behavior annotations do not: `chance_inbred` is null when marks are omitted, and `chance_twins` requires a good-fertility mother — real edge conditions that affect how results are read.

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 topic is front-loaded in the first clause, and the subsequent sentences each explain a distinct output (young_odds, chance_inbred, chance_twins, expected_product_per_hour), so little is wasted. The prose is dense and parenthesis-heavy, which slightly hurts scanability 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?

There is no output schema, so the description carries the burden of explaining returns, and it names every result field and what each means. Given a 5-parameter tool with full schema coverage and clear annotations, the only gap is that it never states the output's container shape or how young_odds is keyed per gene.

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% and the schema already spells out the gene notation, marks range (0-15), and species pattern, so the baseline is 3. The description adds marginal meaning — that omitted genes default to ok/ok and that missing marks drive the null inbreeding result — but no extra syntax or validation detail.

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 pairing: it computes sheep/cow breeding odds covering genes, inbreeding, twins, and wool/milk yield, and anchors this to the animal breeder calculator. An agent can tell this is a genetics-probability tool. It does not explicitly name how it differs from siblings like genetics_predict or genetics_best_layout, so it stops short of a 5.

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?

Usage is only implied: you call it when you want per-gene odds for a given mother/father pair. There is no statement of when not to use it, no pointer to genetics_predict or genetics_best_layout, and no prerequisites beyond an oblique note that gene numbers come from fan tools that read game files.

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