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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. With no output schema, the description usefully discloses what comes back — including the rescue's contact details ('how to reach it') — though it says nothing about lookup failure behavior.

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?

A single dense sentence with the scope front-loaded and no filler; every clause carries information the agent can act on.

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 simple two-param read with full schema coverage and no output schema, the description covers purpose, id provenance and expected return contents. Only edge behavior (unknown id, lang effect) is left unstated.

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 both params are already documented, including id patterns and examples. The description only adds the provenance hint that id comes from find_pets and never addresses lang, so it sits at the baseline.

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?

Specific verb+resource ('One adoptable pet by id') with explicit scope, plus the exact result contents (photos, temperament, good-with, adoption fee, rescue contact). The parenthetical '(from find_pets)' separates it from the list-returning siblings find_pets, show_pets and similar_pets.

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?

'(from find_pets)' tells the agent that the required id originates from find_pets output, which is a concrete chaining cue. It does not, however, state when to use this over get_rescue or what to do on a missing/invalid id.

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