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

Beyond the read-only and idempotent annotations, the description discloses the return format (PNG plus card name, type, and page link), the fallback behavior when images cannot be displayed, authentication requirements for public versus private cards, and billing/requirement status. These are operationally relevant details an agent would not get from the annotations alone.

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 front-loaded with the primary purpose and then layers on only actionable details: parameter constraints, return behavior, fallback handling, auth conditions, display frequency, and cost/requirement status. Every sentence contributes operational guidance without redundant restatement.

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?

Although there is no output schema, the description fully covers the return content and fallback display behavior. It also provides authentication context and usage constraints, making the definition complete enough for an agent to invoke it correctly and interpret its result.

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 coverage is 100%, so the schema already documents the single card parameter. The description adds useful guidance by emphasizing that it must be a card ID or exact reference and never a guessed name, which reduces lookup errors beyond the schema's basic type information.

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 a specific verb and resource: retrieve the image of a Daystruct card, explicitly naming Source, Data, and Memory card types. It also explains the user-facing purpose of showing the card beside the assistant's text, which distinguishes it from the other Daystruct tools.

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 clear when-to-use guidance: introduce, use, update, or report on a card. It also states explicit constraints, including passing an exact ID or reference, not guessing names, showing a card once per response rather than on repeated steps, and that the tool is never required for capability use.

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