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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by naming the metric set returned and by framing this as configured/campaign-level data rather than user-query data. It says nothing about volume, sorting, or aggregation limits, which keeps it below a 5.

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?

One compact paragraph that front-loads the definition, then example intents, then the disambiguation from search terms. The '[DEMO SINTÉTICA]' marker is noise, but otherwise every clause earns its place.

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?

A read-only single-parameter list tool with an output schema, annotations, and a clear sibling distinction — the description covers what an agent needs to select and call it. Only minor operational details (result limits, ordering) are unaddressed.

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?

There is a single optional parameter whose schema description is fully covered (100%), including accepted formats and the default of last 30 days. The description adds no further semantics about date_range, so the schema carries the weight and the baseline of 3 is appropriate.

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 (keywords bid on in Google Ads campaigns) and enumerates the metrics returned: spend, clicks, conversions, CPC, match type. It also explicitly distinguishes itself from search terms, which is exactly the ambiguity a sibling like list_google_ads_search_terms creates.

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?

Provides concrete trigger phrases ('keywords que compramos', 'palabras clave de mis campañas', 'en qué keywords gasto más') and an explicit exclusion rule pointing to search terms for what the user actually typed. An agent can route between the two tools without further inference.

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