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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, covering the safety profile, and an output schema exists. The description adds only the country-filter behavior, with no mention of pagination, rate limits, or result scope, so it adds modest value beyond the structured fields.

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?

A single compact sentence with the key action and option front-loaded and zero filler. It is efficient, though the extreme brevity leaves useful routing detail on the table.

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 output schema offloads return-value explanation, and annotations cover safety, but for a tool sitting among several ads-related siblings the description is too thin to disambiguate when this tool should be chosen over facebook_ads_search.

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%, so both parameters are already documented in the schema, and the description's 'optional country filter' merely restates that. No extra syntax, format, or defaulting semantics are added, so the baseline 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 a specific verb and resource: search ads by keyword, with a country scope. However, it does nothing to distinguish itself from the sibling facebook_ads_search (or facebook_ads_archive_details), so an agent cannot tell from the description alone which of the ads tools to pick.

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?

No when-to-use guidance, no exclusions, and no mention of the sibling facebook_ads_search, which appears to overlap in function. Usage is only implied by the word 'Search'.

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