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

Annotations already declare read-only, idempotent, closed-world, non-destructive, so the safety profile is covered; the description adds the data provenance (Merck Veterinary Manual dose thresholds) and the output behavior (emergency level derived from weight + amount). It stops short of saying what is returned when weight or amount is omitted, which is the one behavioral unknown left.

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?

Front-loaded with the core action and substance list, followed by two short caveat sentences that each carry real signal. The parenthetical substance list is long but earns its place by defining scope; otherwise there is no filler.

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?

With no output schema, the description does enough: it names the two outputs (toxicity verdict and emergency level) and the caveats a safety-sensitive agent must convey. Slightly more on partial-input behavior (substance only vs. substance + weight) would close the remaining gap.

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 every parameter including lang and variant is already documented in the schema. The description reinforces weight and amount as the inputs that drive emergency-level computation but adds no format or fallback rules beyond that. 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 ('Check whether something a dog or cat ate is toxic') and enumerates the covered substances plus the dose-threshold emergency-level output. It is unmistakable against siblings like find_vets or get_breed, which share no domain function.

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?

Sets a clear context (pet ingestion triage) and two explicit boundaries: unlisted substances are NOT confirmed safe, and the tool is a triage aid, not a diagnosis. It doesn't name an alternative tool or say when not to call it, but the sibling set is unrelated so the gap is minor.

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