Promotion: services by listings

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

Annotations already provide readOnlyHint, etc. Description adds value by emphasizing 'spends NO money' and clarifying the return structure (service details and dates). No contradictions.

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: first explains output, second reinforces read-only and differentiates from suggests. No wasted words, front-loaded with purpose, excellent structure.

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 tool with no output schema, the description sufficiently explains return format (slug, name, dates). Input schema is well-documented, annotations are present, and the description covers behavioral and usage context completely.

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?

Input schema covers itemIds with description, achieving 100% coverage. The tool description does not add extra semantic beyond what schema provides, thus baseline score of 3 is appropriate.

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 the tool returns active promotion services for specified listings, including slug, name, and dates. It distinguishes itself from sibling 'suggests' tool, making purpose very specific and unambiguous.

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?

Provides explicit use case ('find out which promotion is already enabled') and warns not to confuse with 'suggests'. However, it does not differentiate from other sibling tools like promotion_get_bbip_forecasts_by_items_v1, leaving some gaps.

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