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

Annotations already declare readOnly, idempotent, non-destructive and closed-world behavior, so safety is covered. The description adds real behavioral context beyond that: the result cap (25 singles), the ranking basis (today's raw market price in USD), the included fields (set and printing), and the important exclusion of graded values.

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?

Three short sentences, all earning their place: trigger condition first, then ranking/return shape, then a scope caveat. Nothing is padded or restated from the title.

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 an output schema present, return values need not be spelled out, yet the description still orients the agent on cap, ordering and currency. For a read-only, two-parameter, defaulted query tool, 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 100% with only two parameters (a game enum and a limit), so the schema already carries the parameter meaning. The description's 'one game' and the 25-cap statement loosely echo the parameters but add no format or syntax detail beyond it.

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 specific resource (singles cards) plus the ordering and scope ('ranked by today's raw market price', 'in one game right now'), which implicitly separates it from siblings like all_time_highs, price_history and movers. An agent can pick this tool without opening the 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?

It gives an explicit trigger ('Use this when the user asks for the most expensive or most valuable cards in one game right now'), which is clear contextual guidance. It stops short of naming an alternative tool or stating when not to use it, so it doesn't reach the 5 bar.

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