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

Annotations already declare readOnlyHint and idempotentHint, yet the description adds real value beyond them: the 404 behavior for hidden/unknown IDs, the caveat that identity-reviewed branding claims remain unverified, and the explicit 'never signs payments' boundary. These are genuine behavioral constraints an agent could not derive from the annotations alone.

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 and compact, with the payload listed first. The trailing fragments 'No paid delivery certification.' and 'Never signs payments.' are telegraphic and lack framing, reading more as clipped boilerplate than earned content.

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?

With no output schema, the description correctly enumerates what is returned and adds the 404 failure mode, which is what an agent needs. It omits any relation to sibling retrieval tools, which is the main remaining gap.

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?

One parameter with 0% description coverage, and the description says nothing about listing_id — no format, no source, no hint that it is a 64-hex hash. The schema pattern carries the only meaning; the description does not compensate for the coverage gap.

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 (retrieve) and resource (one listing) and enumerates the payload: current grades, first seen, scan count, latest 100 grade observations. The singular framing implicitly separates it from bulk siblings like search_listings/search_services, but it never names an alternative, so it stops 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?

Gives one concrete usage condition — hidden or unknown listings return 404 — which tells the agent this only works on visible listings. However it offers no explicit when-to-use vs get_service, search_listings, or get_scan_report, leaving the routing decision to inference.

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