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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. Beyond that, the description discloses scope exclusions (no pharmacy hours/phone, no patient data) and the multi-input resolution order, which are genuine behavioral facts not present in annotations or schema. It does not discuss result limits or pagination, so 4 rather than 5.

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?

Purpose and return payload are front-loaded in the first clause, followed by scope exclusions and then input semantics. It is one dense paragraph rather than broken-up lines, and the parameter grammar could be skimmed faster, but every sentence carries information and nothing is redundant.

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 5-param, zero-required locator tool with a full output schema and readOnly/openWorld annotations, the description supplies everything the schema and annotations omit: input formats, mutual-exclusion/precedence behavior, scope limits, and the meaning of the service filter. Nothing needed to invoke it correctly is missing.

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 0%, so the description carries the entire burden and does so: zip is defined as a 5-digit US ZIP, address gets an example ('Beverly Hills, CA'), latitude/longitude must be supplied together, the precedence order across the three locators is stated, and service is tied to the response's services code vocabulary. This is substantially more than the bare-typed schema provides.

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 verb+resource ('Nearby CVS store locations') and enumerates the return payload (address, phone, fax, distance, hours, has_pharmacy, services). It also draws an explicit scope boundary — 'Covers general store info only -- no pharmacy hours, pharmacy phone, or prescription/patient data' — so an agent can rule out this tool for pharmacy queries without opening a schema.

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?

Gives clear input-selection guidance and a deterministic precedence rule when multiple locators are supplied ('zip wins, then address, then latitude/longitude'), which is exactly the decision an agent needs. It does not name a sibling tool or say when to prefer another endpoint, so it falls short of the top mark.

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