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

Annotations already flag destructiveHint=true, idempotentHint=true and readOnlyHint=false, and the description correctly reinforces this with 'Overwrites previous values' plus the crucial partial-update semantics ('only the fields you pass are sent'). It adds real behavioral value beyond the annotations, though it says nothing about permissions, error behavior, or whether a status change triggers side effects (e.g. removing from a livestock group).

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 tight sentences: the WRITE prefix and scope land first, the conditional requirement second, the overwrite warning third, with the endpoint as a compact appendix. No filler or redundancy.

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 19-parameter destructive mutation with strong annotations and no output schema, the description covers the essentials an agent needs: partial vs full update, the overwrite risk, and the status/death_date dependency. It leaves a minor gap on what is returned and on whether unlisted-but-required-field combinations can fail.

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 only 21% across 19 parameters, so the description must compensate and it only partly does: it clarifies partial-update behavior, enumerates several status values, and ties death_date to specific statuses. The remaining parameters (sale_date, birth_date, weight, tag_number, father_id/mother_id, market_price, deceased_reason) get no semantic help, though most are self-describing by name.

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 ('change an animal's fields') plus the underlying endpoint (PUT /animals/{animal_id}), which makes it unambiguously the mutation counterpart to farmbrite_create_animal and farmbrite_get_animal. It does not name a sibling explicitly, 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?

Gives the key operational rule that statuses Butchered, Culled and Deceased require death_date, which is genuine when-to-use guidance an agent could not infer. It never names an alternative tool or a when-not-to-use case, so it is clear context rather than full routing guidance.

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