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

The annotations already indicate readOnly=true and destructive=false, so the safety profile is covered. The description adds output specifics (due/new counts) but does not discuss side effects or failure modes, which is acceptable for a simple read-only list.

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 clear sentence with no redundant words. It efficiently conveys the tool's purpose and output.

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-parameter listing tool, the description is complete. It tells the agent what is returned (decks with due and new card counts) and there are no additional prerequisites or context requirements.

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?

There are no parameters to describe, so the schema fully covers this dimension. No additional parameter explanation is needed.

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 clearly states the action (list), the resource (user's decks), and the specific data returned (due and new card counts). It unambiguously distinguishes this from card-level operations.

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 is self-explanatory for a no-parameter listing tool. It does not explicitly contrast with list_cards, but the resource difference is obvious enough that an agent can select this tool correctly.

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