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

With no annotations provided, the description carries the full burden. It discloses the money fields (credits_earned vs gross charged, platform fee, cashout, USD estimates) and period modes, which adds useful behavioral context. However, it does not mention potential side effects (e.g., read-only nature), authentication requirements, rate limits, or error behavior, leaving some gaps for a reporting tool.

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 appropriately sized: it front-loads the core purpose and then adds detail on money fields, placement_id, and period modes. Each sentence earns its place without excessive verbosity, making it easy to scan and parse.

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?

Given the 7 parameters and no output schema, the description provides the core context (placement breakdown and money fields) but lacks details such as how period modes map to date parameters, expected row structure, pagination, or timezone handling. It is minimally complete for an agent to infer usage but leaves some ambiguity for full understanding.

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?

The schema provides 100% coverage of all 7 parameters with clear descriptions, so the baseline is 3. The description redundantly notes 'Optional placement_id' and the period enum values, but it does not add meaning beyond what the schema already conveys, such as parameter relationships or special formatting.

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 explicitly states 'Publisher period breakdown by placement', which is a specific verb (breakdown) and resource (publisher report by placement). It distinguishes itself from siblings by referencing 'same money fields/legend as get_publisher_report' and by the placement-specific scope, making it clear this is a placement-level variant.

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 implies usage context: it's for publisher reporting broken down by placement, and the reference to get_publisher_report suggests a similar field structure. However, it does not explicitly state when to use this tool against alternatives like get_publisher_report_by_campaign, nor does it provide exclusions or conditions for selection.

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