campaign_performance

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

With no annotations, the description carries the full burden of explaining behavior. It discloses the read-only reporting nature, the included metrics, date range, and ordering. However, it does not describe the return format, pagination, or what happens when no data matches, which would be useful 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 a single, front-loaded sentence that includes the core action, metrics, date format, and sort order. Every phrase earns its place with no repetition or filler.

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?

The description covers the primary reporting purpose, metrics, date range, and ordering. However, with no output schema and no annotations, it leaves gaps around limit behavior, customer_id scope, and result shape. More detail would make the tool self-contained for an agent.

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 0%, so the description must compensate. It adds meaning for start_date and end_date by specifying YYYY-MM-DD, and implies the report content, but it does not explain customer_id or limit semantics. This is only partial compensation for an undocumented schema.

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 begins with the verb 'Report' and a specific resource, 'per-campaign performance', and enumerates concrete metrics (impressions, clicks, cost, conversions). This clearly distinguishes it from siblings like list_campaigns, which simply list campaigns without performance data.

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 provides clear usage context by specifying the date range format and the sort order ('highest spend first'). It does not explicitly mention alternatives or exclusions, but the purpose and constraints are clear enough for an agent to select this tool when campaign performance metrics are needed.

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