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

With no annotations, the description carries the full behavioral disclosure burden. It clearly explains deduplication vs. first-discovered semantics, that creative counts use lifetime overlap, and that no paging is needed. It does not mention response format, rate limits, or authorization requirements, but for a counting tool the disclosed behaviors are the meaningful ones.

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?

Three front-loaded sentences with no fluff. The first sentence states the result sorts and scope; the second clarifies the metric semantics; the third gives usage guidance. Every sentence 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?

For a four-required-parameter tool with no output schema and no annotations, the description covers the core behaviors: metric definitions, date-range semantics, no paging, and when to use it. It does not describe the response envelope or edge cases (e.g., empty results), but the absent output schema makes that a minor gap rather than a serious omission.

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%, giving a baseline of 3. The description adds real value by defining how date_from/date_to relate to counts: 'Creative count uses lifetime overlap; first-discovered count uses first appearance within the range.' It also reiterates the 180-day max range, reinforcing implicit schema constraints.

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 the exact resources and metrics ('deduplicated creative count, first-discovered creative count and ad-plan count') and scopes the operation to 'one game, platform and explicit date range'. It also differentiates itself from siblings by instructing agents to 'Always use this tool for platform totals rather than counting pages from discovery tools.'

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 guidance is given: 'Always use this tool for platform totals rather than counting pages from discovery tools' tells agents when to use it instead of alternatives. 'No paging is needed' proactively prevents unnecessary pagination calls. The explanation of dedup semantics and the 180-day cap further clarifes when the tool is appropriate.

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