See performance

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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description adds the useful detail that values are 'real' account metrics (spend, clicks, conversions), but says nothing about time range, granularity, or scope of the returned data.

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?

A single front-loaded sentence with the metric list up front and no filler. Efficient, though extremely terse for the scope it covers.

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 zero-param read tool with no output schema, the description names the metrics but leaves the temporal scope unexplained -- 'real spend' over what window is ambiguous with no date parameter available. Adequate but incomplete given the missing output schema.

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 tool takes zero parameters, so per the rubric this defaults to a 4. There is nothing for the description to clarify beyond confirming the no-argument nature.

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?

States a specific verb and resource ('See ... from your connected ad account') and enumerates the returned metrics (real spend, clicks, conversions). It is clear what the tool does, though it does not distinguish itself from nearby siblings like get_brand_stats or get_account_performance-style stats 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?

The description offers no when-to-use guidance, no prerequisites, and no alternatives. With siblings such as get_brand_stats, get_brand_ads, and list_ad_accounts in the same space, the agent gets no signal on when this tool wins over those.

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