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

Annotations already indicate this is not read-only, so the description doesn't need to restate mutation. It adds useful behavioral detail: decks are created empty, Parent::Child creates parents automatically if missing, and create_cards will create its own deck. This goes beyond the schema and annotations.

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 informative, with the core action first, then naming mechanics, then a practical pointer to an alternative. There is no filler or repetition of schema/annotation information.

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 simple two-parameter tool with an output schema, the description is complete. It explains key side effects (parent auto-creation), the empty-deck nature, and the relationship to create_cards. The output schema covers return details, so nothing essential 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?

With 0% schema description coverage, the description must explain parameters, and it does for the required 'name' by documenting the Parent::Child delimiter and implicit parent creation. The optional 'description' parameter is not mentioned, but the required parameter is well covered.

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 a specific action ('Create a new (empty) deck') and identifies the resource. It also distinguishes itself from the sibling create_cards by noting that create_cards creates its own deck, so there is no ambiguity about what this tool does.

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 the tool is 'Not needed before create_cards, which creates its deck,' giving an explicit when-not-to-use condition and naming the alternative. It also implies use it when you need a standalone empty deck, especially with subdeck naming.

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