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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that results are paginated and that each item carries its causing promotions, but says nothing about auth requirements, rate limits, or where the underlying store id comes from (that lives in the schema). Adequate given annotation coverage, but not rich.

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?

Two sentences, no filler. The purpose and scope lead, and the disambiguation against siblings is packed into the second sentence. Nothing is repeated from the schema or annotations.

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?

An output schema exists, so return-shape explanation is unnecessary, and annotations plus a fully documented 5-parameter schema cover the rest. The only real gap is the absence of a pointer to where store_id originates or any pagination-termination hint, both minor for a read-only listing 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?

Schema description coverage is 100%, including unusually thorough notes on the inert lat/lon and the skip/limit ranges, so the schema carries the entire parameter burden. The description adds no parameter meaning of its own; baseline 3 applies when structured fields do all the work.

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 (Fetch), resource (discounted items), scope (one 7NOW store), and even the payload composition (each promotion that causes the discount). It explicitly contrasts itself with the sibling tools sevennow_offers and sevennow_promotion, so an agent can route 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?

The second sentence names two alternatives and what each returns ('store offers' vs 'one promotion's details'), which is real routing guidance rather than vague context. It falls short of 5 only because it doesn't state the positive selection condition (e.g. 'use this when you want per-item discounts with their causes') in as many words.

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