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 genuine value beyond them by naming the metric set and the paid-only scope, though it says nothing about data freshness, attribution windows, or account/permission requirements.

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?

The core purpose, metric list and scope caveat are all front-loaded and waste-free. The "[DEMO SINTÉTICA]" prefix and the long quoted alias list consume space but serve retrieval matching rather than the calling agent.

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 structure need not be explained, and the description still enumerates the key metrics and the paid-vs-organic boundary. For a one-parameter read-only summary tool, an agent has everything needed to select and invoke it correctly.

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 with 100% schema description coverage, including accepted formats and the default of last 30 days. The description adds no parameter guidance beyond that, so the baseline of 3 applies.

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 (Meta Ads / paid Facebook & Instagram advertising) and enumerates the exact metrics returned (spend, reach, impressions, clicks, CTR, CPM, messages, leads, purchases). It also draws an explicit boundary against organic Instagram, which separates it from get_instagram_summary and get_analytics_summary without opening their schemas.

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 rich set of trigger phrases ("cuánto gastamos en Meta", "anuncios de Facebook") and an explicit exclusion ("Solo publicidad pagada; no incluye Instagram orgánico"). It stops short of routing the agent to the natural drill-down sibling, list_meta_ads_campaigns, when campaign-level detail is needed instead of a summary.

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