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

Beyond the readOnly/openWorld annotations, the description discloses meaningful behavior: it returns both bid and free placements, includes card opens and click-throughs, orders by 'newest attention first,' and can be filtered to one category. This gives a clear picture of what the agent will receive without relying solely on annotations.

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 compact and front-loaded: it states the core purpose first, then the row contents, then the intended downstream use. Each sentence adds necessary information, and there is minimal filler or repetition.

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?

Even without an output schema, the description communicates the main return fields (card opens, click-throughs, bid vs free placement, brandId) and the ordering behavior. It also names the primary downstream consumer, making it fully actionable for an agent deciding whether and how to call it.

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%, so the schema already documents both limit and category. The description adds context for category by calling it optional and mentioning filtering, and it implies limit affects result count, but it does not add significant meaning beyond the schema. Baseline 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 names a specific verb and resource — listing brands tied to advertising slot history — and clearly distinguishes itself from siblings like get_brand_stats by stating 'Use this to find a brandId for get_brand_stats.' It also clarifies the exact scope: brands that held or contested a twelve-hour advertising slot.

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 description gives a clear primary use case: retrieving a brandId for get_brand_stats. It also explains optional category filtering and the sort order. However, it does not explicitly state when to avoid this tool or name alternatives such as list_winners, so it stops short of full when-to-use-versus-alternatives guidance.

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