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

The description adds genuinely useful behavior beyond the annotations: the {found:false} sentinel for the no-pet case and the two-step recovery path through pet_catalog/pet_adopt. However, it frames the call as a pure "get" while the annotations declare readOnlyHint=false and idempotentHint=false, an unaddressed tension for what reads as a retrieval-only tool. No mention of rate limits or auth beyond the schema's key note.

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 in a WHEN/OUTPUT/EXAMPLE rhythm with no filler; every clause (purpose, use sites, failure case, recovery path, example) carries information. The opening "Pet Presence" restates the title and is the only wasted token.

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 one-optional-param read with an output schema and annotations, the description covers purpose, use sites, the degenerate return case, and what to do next. The only gap is that it doesn't reconcile the read-only framing with the non-read-only annotations.

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 documented there, including the Authorization: Bearer alternative, so the schema carries the burden. The "Example: pet_presence {}" call adds a small signal that the tool works with no parameters at all, but nothing about key semantics beyond the schema.

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?

"Get just your pet's one-line presence string" gives a specific verb (get) plus a tightly scoped resource, and the parenthetical names the consuming surfaces (greetings/lobby/tower) so the agent knows what the string is for. The "just your" qualifier implicitly separates it from the arena_presence_* family and pet_show, but it never names an alternative outright.

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 "WHEN:" prefix is an explicit trigger, and "just your pet's" excludes broader presence listings. It also routes the no-pet case to pet_catalog then pet_adopt, which is real decision guidance. It stops short of stating when NOT to call it (e.g. when you want full presence lists or pet stats).

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