Ad Details

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

Goes well beyond the annotations: it discloses credit consumption, the confirm=true gate, cache-vs-live behavior implications, and explicitly reconciles the readOnlyHint=false annotation by noting that read-like POSTs do not publish to social platforms. It also warns that multi-version ads hide the creative in snapshot.cards rather than snapshot.body, a genuinely useful behavioral caveat.

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?

Purpose and the credit/confirm requirement are front-loaded, and most sentences carry load-bearing detail about return shape. It is dense and slightly over-stuffed, and the dangling phrase 'using the structure shown below' references something that is not actually present, which costs it a point.

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 correctly assumes the burden of describing return values (adArchiveID, pageName, snapshot fields, aaa_info, normalized political delivery fields) and even clarifies units (0.08 = 8%). An agent has everything needed to interpret the response.

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 the schema already documents every parameter including the enum and the account/confirm semantics, establishing the baseline of 3. The description's confirm/credit note and ID-or-URL mention echo the schema rather than adding new parameter-level syntax or constraints.

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+resource (retrieves detailed information about a specific Facebook ad) and the required identifier (by its ID or URL), which inherently separates it from the search/company_ads siblings in the same family. It also enumerates the returned fields, leaving no ambiguity about what this tool produces.

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 establishes the calling context (you must already have an ad ID or URL) and a hard prerequisite (confirm=true consumes paid credits). It stops short of explicitly naming the alternative (e.g., use facebook_ad_library_search when you only have a query), so it falls just below the when/when-not/alternatives bar.

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