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

Annotations already establish read-only, idempotent, non-destructive and closed-world behavior, so the bar is lower. The description still adds real context: no inputs are needed, the deal may be absent ('or the statement that none is live'), deals rotate daily, and they stack with quantity discounts. Only minor gaps remain, such as caching or freshness guarantees.

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?

Content is front-loaded with the purpose, then routing, then return behavior, then example phrasings. The quoted customer phrases are somewhat list-heavy but serve retrieval matching; otherwise the prose is tight.

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?

With rich annotations, an output schema, and zero parameters, the description covers everything an agent needs: what it returns, the zero-result case, and how it differs from siblings. No material gap remains for a simple lookup tool.

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 takes zero parameters, so the baseline is 4. The description confirms this explicitly ('Takes no input'), which is consistent with an empty schema and prevents an agent from inventing filters.

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?

States a specific verb and resource ('Shows today's 4OVER4 printing deal') and enumerates the returned fields (product, discount, code, sale price). It also names the sibling tools it is not (search_knowledge for discount policy, price_breaks for bulk savings), so an agent can route correctly without opening any 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?

Explicit when-to-use conditions are given ('when someone asks for a print deal, discount or promo today') plus concrete customer phrasings that trigger it. Two alternatives are named with the conditions that select them instead, leaving nothing to inference.

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