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

With no annotations provided, the description must fully disclose behavior, but 'Facebook Ad Library' reveals nothing about side effects, required permissions, rate limits, or response characteristics. It is a bare label, not a behavioral explanation.

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 exceptionally short, but this is under-specification rather than effective conciseness. It contains no actionable information and fails to earn its place as a standalone description.

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 four parameters, no output schema, no annotations, and a large set of sibling tools, the description leaves nearly all contextual gaps unfilled. It does not explain what inputs mean in context, what the output looks like, or how this tool relates to other ad library tools.

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 baseline is 3. The description itself adds no parameter meaning beyond what the schema already provides, but the schema adequately names 'Ad ID', 'Ad URL', 'trim', and 'get_transcript' with short explanations.

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 'Facebook Ad Library' merely restates the tool name without providing a verb or action. It does not say whether the tool searches, scrapes, or retrieves ads, nor does it distinguish it from sibling tools like scrapecreators_search_ads or scrapecreators_ad_details.

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?

There is no guidance on when to use this tool versus alternatives. Among many ad-related sibling tools, no context, prerequisites, or examples are given, leaving the agent unable to decide on appropriate usage.

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