Get Ad Preview

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the either/or input constraint, which is a usage constraint rather than a behavioral disclosure, and does not mention return format or error handling, but the read-only nature is well established by the 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?

The description is compact, front-loads the core purpose, and presents the arguments in a scannable list. The final 'Provide either ad_id or creative_id' is a necessary constraint, and there is no redundant filler.

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 description covers the tool's purpose, key parameters, and the mutual-exclusion constraint. There is no output schema, so a note about the response structure would have been helpful, but the description already states it generates a preview URL. Missing edge-case behavior for providing both or neither ad_id and creative_id is a minor gap, but the tool is otherwise clear.

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 only 25% (only response_format has a schema description), so the description must compensate. It explains ad_id, creative_id, and ad_format, but lists only five of the seven enum values for ad_format, omitting MARKETPLACE_MOBILE and AUDIENCE_NETWORK_OUTSTREAM_VIDEO. It does not mention response_format, but that parameter already has a schema description, so overall it adds meaningful semantics for most parameters.

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 uses the specific verb 'Generates' and names the resource 'preview URL for an ad or creative,' which clearly distinguishes this from sibling tools like meta_get_ad or meta_get_ad_creative that retrieve details. It also explicitly lists the two mutually exclusive identifiers, making the core function unambiguous.

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 provides the 'Provide either ad_id or creative_id' constraint, but this is an argument-level guideline, not a tool-selection guideline. It does not explicitly state when to prefer this tool over siblings such as meta_get_ad or meta_get_ad_creative; the intended context is implied by the word 'preview' rather than stated.

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