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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, and the description's 'No writes or access grants' merely restates that. It does add genuine context by disclosing an access prerequisite and a refusal behavior for restricted services, but 'fresh server-verified access' is too vague to act on and no failure mode or return behavior is described.

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?

Three short sentences with no filler, and the core action is front-loaded. However, the middle sentence is cryptic boilerplate that consumes space without conveying actionable meaning to the caller.

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?

An output schema exists so return values need not be explained, but the required 'body' object has no declared properties and no description, and the description offers no hint about what insight or filters belong in it. For a nested-object benchmark tool this leaves a material calling 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 coverage is only 33%: customer_id is documented but connection_context is undocumented and body is an empty object with additionalProperties=false, which is the critical unknown. The description says nothing about any parameter, so it fails to compensate for the coverage gap.

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?

It names a verb ('Read') and a resource ('benchmark_locations insight'), so the general domain is identifiable, but modifiers like 'bounded' and 'native' are unexplained jargon. It does nothing to distinguish itself from the many closely named siblings (google_ads_benchmark_dates, _metrics, _products, _sources, google_ads_reach_locations).

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?

There is no statement of when to call this versus the other benchmark_* or reach_locations tools, and no preconditions beyond a vague note that restricted services need 'fresh server-verified access'. The agent is left to infer selection purely from the name.

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