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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds the meaningful behavioral detail that results are grouped counts rather than records, but says nothing about rate limits, token needs, or data recency beyond what the schema already states.

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 tight sentences: the capability statement leads, the usage examples follow. No filler, though the parenthetical outcome list is slightly redundant with the outcome_type enum.

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 low-complexity, zero-required-parameter aggregate tool with no output schema, the description conveys what is counted and how it can be grouped, which is sufficient to call it correctly. Only the exact shape of the returned summary is left implicit.

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 each parameter (since, group_by, _apiKey) is fully documented in the schema itself, including the May 2025 data floor and the app-token behavior. The description's grouping list maps to the group_by enum but adds no syntax or format detail beyond the schema, so baseline 3.

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 resource (Austin Animal Center outcomes) and operation (summary counts) plus the grouping dimensions, so an agent can tell it apart from austin_recent_intakes and austin_search_animal by scope. It stops short of naming a sibling or alternative, so a 4 rather than 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?

The description gives two concrete example queries ('how many animals were adopted', 'Austin shelter euthanasia rate') that clearly signal the aggregate/historical use case. It offers no explicit when-not guidance or named alternative, so it is strong context but not full routing.

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