Search Meta ads

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description doesn't need to repeat safety. It adds behavioral details beyond annotations: cost ('Spends a credit or two') and return format ('Returns compact JSON {page_name, body, cta, link, dates, media} per ad'). It doesn't reveal pagination or empty-result behavior, but the annotations cover the core safety profile, making this a solid 4.

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 description is four sentences with zero fluff. The core purpose and usage guidance are front-loaded, cost is mentioned concisely, and the return format is succinctly defined. Every sentence 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?

With no output schema, the description provides the return structure explicitly. It covers cost, usage context, and names the alternative tool. It lacks pagination details or limits beyond the 'limit' parameter, but for a 7-parameter tool with full schema coverage and clear annotations, it is complete enough for an agent to call 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?

Schema coverage is 100% with detailed parameter descriptions, so the baseline is 3. The description adds value by clarifying the mutual exclusivity rule: 'a keyword (query) OR one advertiser (companyName / pageId)'. This is not present in the schema and helps an agent choose between parameters correctly, raising the score to 4.

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?

The description states a specific action ('Structured Meta (Facebook/Instagram) Ad Library pull') and the resource, and explicitly names the sibling tool it is not ('For open-ended research... use research_ads instead'). It clearly distinguishes itself from other search tools like search_google_ads by framing it as a precise pull when you know exactly what to fetch.

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 description gives explicit usage conditions ('use when you know exactly WHAT to fetch') and names the alternative for open-ended research ('use research_ads instead'). It also adds practical cost guidance ('Spends a credit or two'), which is valuable for an agent deciding when to call this tool.

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