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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: an explicit 'Requires sign-in' auth precondition and a full enumeration of returned fields (list_id, title, kind, role, item count, recipient, event date, links), which matters because there is no output schema.

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 sentences, front-loaded with the scope statement, and every clause earns its place — the second sentence substitutes for a missing output schema. It is dense and slightly run-on in the return-field enumeration, but there is no filler.

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 no-output-schema read tool it covers the essentials: what is returned, per-list attributes, and the sign-in requirement. Gaps are minor — no mention of ordering, pagination or size limits on the result set, which an agent may want before calling on a large account.

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?

The single `market` parameter has 100% schema description coverage including its enum and default, so the schema carries the meaning. The description does not mention `market` at all and adds nothing about how it affects the returned links; per the high-coverage baseline, 3 is the ceiling.

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 and resource ('Returns the lists on the signed-in shopper's Plendio account') and then disambiguates the resource by enumerating the three kinds (wishlists, shopping lists, favourites) plus the owned-vs-shared distinction. That scope definition lets an agent separate it from singular siblings like get_wishlist or get_my_wishlist 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?

Usage is implied by the scope: call this when you need an overview of every list the shopper can see. It never names an alternative (get_wishlist, get_my_wishlist, list_shares) or states when not to use it, so routing between the several list-related siblings is left to inference.

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