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

Annotations already declare readOnly, idempotent, open-world, and non-destructive behavior, so the safety profile is covered. The description adds material context beyond that: it requires the caller's own RescueGroups API key and explains that key provisioning is manual and not instant. It does not discuss pagination behavior or result ordering, but with strong annotation coverage this is a solid 4.

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?

The description is front-loaded with purpose and returned fields, then moves to filters, the API-key requirement, and one example. Every sentence earns its place, though the example partially duplicates the schema's own examples, making it slightly longer than strictly necessary.

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 14-parameter search tool with no output schema, the description does the important work: it lists the returned fields, explains the credential prerequisite, and shows a realistic filter combination. It omits any mention of the single-organization fetch mode (org_id) and pagination behavior, which keeps it short of complete.

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 the schema and annotations already document all 14 parameters in detail. The description's 'filter by postal-code radius, state or name' and its example reinforce a subset of parameters but add no syntax beyond the schema. The baseline 3 is appropriate.

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?

The description states a specific verb and resource: 'Find animal rescues and shelters with RescueGroups.org accounts,' then enumerates the fields returned (name, type, address, phone, email, website, adoption process, areas served, services). It is clear what the tool does and how it differs in substance from the animal/breed/species sibling tools, though it never names a sibling explicitly, keeping it short of 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?

It gives concrete usage context: filter by postal-code radius, state, or name, and it notes the API-key prerequisite. The inline example shows a realistic search invocation. There is no explicit 'when-not' guidance (e.g., use org_id to fetch a single org rather than searching) and no discussion of alternatives, so it lands at 4 rather than 5.

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