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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: results are ordered 'newest first', and the tool is a lookup step for set ids. It doesn't mention pagination or response shape, but the output schema exists and the annotations carry the safety burden, so this is solid.

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 sentences, all information-dense. The primary use case is front-loaded, the ordering behavior is stated, and the exclusion is a single short sentence. No filler or repetition of schema details.

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 read-only list tool with an output schema, the description covers the key context: when to call it, what it returns (set ids), ordering, and what it is not for. It doesn't mention pagination or how to handle large result sets, but the limit parameter and output schema cover most of what an agent needs.

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 only 33% (only 'query' has a description), so the description must compensate. It does: it explains the purpose of the 'game' parameter via examples and clarifies that the tool returns set ids. It doesn't detail 'limit' semantics, but the schema already has a default and min/max, so the marginal gap is small.

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 states a specific verb ('find the set id'), a clear resource (sets/expansions), and gives concrete examples ('Evolving Skies', '2019 Panini Prizm'). It also explicitly distinguishes itself from get_set_cards and search_cards by naming the intended use case, so an agent can tell it apart from siblings 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?

The description explicitly says when to use it ('before calling get_set_cards, or when the user asks which sets exist') and when not to use it ('Do not use to price a single card'). This is strong routing guidance that names the alternative behavior and the exclusion condition.

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