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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds real value by disclosing what comes back — the rule expressed in words and the end date — which tells the agent results are human-readable rather than structured rules. Pagination and result volume are unaddressed.

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?

A single sentence that front-loads the core purpose and uses the parenthetical to enumerate promotion types without waste. Every clause earns its place.

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 no output schema, the description usefully previews the return shape (rule in words, end date), and the annotations cover the safety profile. It is nearly complete; only result size/pagination behavior is left to discovery.

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% and the single `store` parameter is documented in the schema with a helpful hint about where to source the id. The description adds nothing about the parameter, so baseline 3 applies.

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 names a specific verb (listing promotions running now) and resource, and enumerates the promotion subtypes (free shipping, buy X pay Y, combo, gifts) so the agent knows exactly what domain this covers. No sibling tool addresses promotions, and the phrasing distinguishes it clearly from product/store lookups.

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?

Usage is only implied — an agent can infer this is for answering 'what deals are active?' questions, but the description never states when to call it or when not to. Since no sibling overlaps, the absence of named alternatives is tolerable but leaves routing to inference.

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