get_pixel_event_stats_tool

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does disclose the output shape ('Returns one row per pixel per event type per day') and the prerequisite for pixel_ids. This gives the agent a good sense of what to expect and what is needed. It does not explicitly state that the operation is read-only or has no side effects, but the 'get' prefix and the nature of the tool imply a safe read operation. It also doesn't mention rate limits or error handling, but for a stats tool, the provided details are sufficient. The output format and prerequisite are valuable behavioral traits beyond the schema.

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 three sentences, each adding distinct value: purpose, usage prerequisite, and output/date format. It is front-loaded with the core purpose, and there is no fluff or redundancy. It is efficient and well-structured, earning a high score.

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 tool has 4 parameters, no annotations, and an output schema is indicated. The description covers the purpose, the output shape ('Returns one row per pixel per event type per day'), and the prerequisite for pixel_ids. It also specifies the date format. It does not mention potential limits (e.g., date range restrictions, pixel count limits) or error conditions, but given the output schema exists and the tool is relatively simple, the description provides enough context for an agent to call it correctly. The missing advertiser_id clarification is a minor gap.

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 clarifies the date format: 'Dates are YYYY-MM-DD,' which directly explains start_date and end_date. It also explains the source of pixel_ids: 'Use after get_pixels_tool to get pixel_ids.' This adds meaning beyond the raw schema. It does not explicitly describe advertiser_id, but that is likely self-explanatory from its name. The description also ties pixel_ids to the output granularity ('per pixel'), which is helpful. Given the zero coverage, it does a good job of illuminating the key parameters, though it could have added a brief note on advertiser_id.

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's function: 'Get aggregated conversion event counts (Purchase, AddToCart, ViewContent, etc.) per pixel over a date range.' It specifies the resource (pixel event counts), the action (get), and the scope (per pixel, per date range). It also distinguishes itself from siblings by mentioning 'Use after get_pixels_tool to get pixel_ids,' indicating a specific workflow that separates it from other reporting tools. This is a specific verb+resource with clear differentiation.

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 a clear usage prerequisite: 'Use after get_pixels_tool to get pixel_ids.' This tells the agent that pixel_ids must be obtained from another tool first, which is a concrete when-to-use instruction. However, it does not explicitly compare with alternative reporting tools like get_reports_tool or the async report tools, nor does it state when not to use this tool. It gives clear context but lacks explicit exclusions or alternatives.

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