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

The annotations already cover the safety profile (readOnly, non-destructive, closed-world), yet the description still adds real value: it discloses the shape of the response and a conditional behavior — market value is only returned for Premium accounts. That entitlement gate is exactly the kind of context annotations cannot express, though it omits scope/pagination detail.

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 short sentences, front-loaded with the resource and its contents, followed by the single conditional caveat. Nothing is wasted and nothing important is buried.

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 does a fair job of enumerating what comes back, and the Premium gate is disclosed. However, for a two-parameter tool with zero schema documentation, the complete silence on how game and language scope the summary leaves a genuine 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?

Schema description coverage is 0% with two parameters (game, language) that have no documented meaning anywhere. The description does not mention either parameter, so an agent cannot tell what values are accepted (e.g., which game identifiers, which language codes) or whether omitting them aggregates across everything.

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 names a concrete resource (the user's binder/collection) and enumerates the contents of the summary: copy counts, doubles, wishlist, sealed products. This lets an agent recognize an aggregate-overview tool, though it never explicitly distinguishes itself from sibling aggregation tools like portfolio_analysis or set_completion.

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 only implied — an agent can infer this is the tool for a high-level snapshot rather than the granular list_doubles/list_wishlist/list_sealed tools, but the description never says so. There are no stated exclusions or named alternatives despite several overlapping siblings in the toolset.

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