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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful return-field context (impressions/clicks/cost/conversions) and a default 30-day window, but omits auth needs, rate limits, and pagination behavior.

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?

Two tight sentences front-load what the tool returns, then add a use case and a default behavior. Every sentence earns its place with no wasted wording.

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 purpose, use case, returned metrics, and a default date range, which is helpful because annotations cover safety. But for a 4-parameter tool with zero schema descriptions and no output schema, it is thin on parameter guidance and does not fully compensate for the missing structured documentation.

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?

With 4 parameters and 0% schema description coverage, the description must carry the burden of explaining parameters. It only hints at the date default ('last 30 days') and says nothing about limit, customerId, or date formats, leaving most parameter meaning undocumented.

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 the specific resource (actual search queries that triggered ads) and the metrics returned, so the agent knows what the tool produces. However, it does not differentiate this report from sibling report tools such as run_report or get_ad_performance, which limits it to a 4.

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?

Gives a clear use context—spotting wasted spend and finding negative-keyword candidates—which tells the agent when the tool is valuable. It does not name alternative tools or specify when not to use it, so it falls short of a 5.

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