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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered structurally. The description adds that the data is synthetic ([DEMO SINTÉTICA]) and which metrics come back, but says nothing about aggregation granularity, time-zone handling, or empty-data 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?

Purpose and metric list are front-loaded in one sentence, followed by a routing keyword list. The keyword list is somewhat redundant filler, but it is short and serves query matching.

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, and the single optional parameter is fully covered by the schema. What is missing is only the relationship to the per-entity Google Ads list siblings, which is a minor gap for a simple read-only summary.

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 100%: the single date_range parameter is documented with examples and a default (últimos 30 días). The description adds nothing about the parameter, so the baseline 3 applies — the schema does all the work.

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 resource (Google Ads performance) and enumerates the metrics returned (spend, impressions, clicks, CTR, CPC, conversions, CPA, ROAS), which clearly marks it as the aggregate summary rather than a per-entity listing. It does not explicitly name the sibling list tools it replaces, so differentiation is implied by the metric list rather than stated.

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 quoted trigger phrases ("cuánto gastamos en Google", "campañas pagas", "anuncios de Google") give an agent a clear signal for when this tool applies. However, there is no exclusion guidance — nothing says to use list_google_ads_campaigns or list_google_ads_keywords instead when a breakdown is needed.

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