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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent action, and the description adds genuine behavioral detail beyond them: hygiene increases while happiness drops slightly, and the pet "resists baths" so the gain is small. It still says nothing about cooldowns, repeat-call behavior, or preconditions such as the pet being present.

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?

Two compact sentences plus a concrete call example, with the trigger condition front-loaded. Nothing is padded, though the unexplained "Cheeky" reference costs a little clarity for the space it occupies.

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 one-action tool with an output schema and full annotation coverage, the description supplies the effect, the cost, and a usage example. Only edge-case behavior (repeat calls, failure modes) is absent, which is minor at this complexity.

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 coverage is 100% and the single "key" parameter is already documented there, so the schema carries the burden. The `pet_clean {}` example usefully signals that the call works with no arguments, but adds no syntax or format detail beyond that.

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?

Names a specific verb+resource ("clean your pet") and states the outcome ("hygiene up"), which separates it from pet_feed, pet_play and pet_rest. The mention of "Cheeky" is unexplained and reads as a persona name rather than a scope statement, which slightly muddies the picture.

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 explicit "WHEN:" prefix plus the stated trade-off ("small gain, tiny happiness cost") gives the agent enough to decide whether to act. It stops short of naming alternatives or a when-not-to condition, 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.