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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is well-covered. The description adds that the tool returns all sets with specific fields, which is useful but does not elaborate on other behavioral aspects like pagination or dynamic data. Given the annotations, the description provides adequate but not exceptional transparency.

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?

The description is a single, concise sentence (18 words) that front-loads the verb and resource. Every word provides necessary context, and there is no redundancy or fluff.

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?

Given the tool's simplicity (no parameters, no output schema), the description fully covers what the tool does and what it returns. It lists the exact fields returned, which compensates for the lack of an output schema. The tool is a straightforward list, so no additional context is needed.

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 tool has zero parameters, and the input schema is empty with 100% coverage. The description correctly implies no inputs are needed, so it adds no unnecessary information. This is ideal for a parameterless tool.

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 uses the verb 'List' and specifies the resource 'Magic: The Gathering (MTG) sets/expansions', clearly indicating the tool's purpose. It also enumerates the exact fields returned (codes, names, types, release dates, card counts), which distinguishes it from sibling tools that deal with cards (e.g., search_cards, get_card).

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 clearly implies that the tool should be used when a complete list of MTG sets with their metadata is needed. While it doesn't explicitly mention when not to use it or provide alternatives, no sibling tool performs a similar function (listing sets), so the guidance is clear enough for an agent to choose correctly.

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