Search Meta ads

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

Annotations already declare readOnlyHint and openWorldHint. The description adds further behavioral details: returns compact JSON with specific fields, consumes ~1-2 credits, and is structured (vs open-ended). No contradictions, and it goes beyond annotations.

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?

Two concise sentences with no filler. The purpose is front-loaded, and every sentence adds value: definition, usage guidance, return format, alternative tool, and credits.

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?

Given the output schema exists, the description need not elaborate on return values. It covers the key differentiator (vs research_ads), credits, and mutual exclusivity. For a search tool with good annotations and schema, it is quite complete. Minor gap: no mention of rate limits or error conditions.

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%, so parameters are documented. The description adds mutual exclusivity guidance (keyword OR advertiser) and default limit of 8, which adds meaning beyond the schema. However, it doesn't detail the exact format of certain parameters beyond what the schema provides.

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 clearly states it is a structured Meta Ad Library pull, specifies the exact use case (know what to fetch: keyword or one advertiser), and distinguishes it from the sibling 'research_ads' tool. The verb 'pull' and resource 'Meta Ad Library' are explicit.

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 explicitly tells when to use this tool ('know exactly WHAT to fetch') and when not to use it (for open-ended research, use 'research_ads' instead). It also mentions credit consumption, aiding the agent in cost-aware decision-making.

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