check_ad_post

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description reinforces this by describing validation rather than mutation. 'Surfaces platform errors' adds useful behavioral information about what the tool reveals. There is no contradiction with 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?

Two short sentences with the core action and timing front-loaded and no filler. Each sentence earns its place, and the second adds a behavioral detail without bloating the 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?

For a two-parameter validation tool, the description plus rich annotations and an output schema provide enough for an agent to invoke it correctly. The main gaps are only limited parameter-specific details and lack of explicit routing among sibling tools, which are minor given the tool's low complexity.

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 0%, and the description only restates the two parameters as 'promote URL + text' without adding formats, constraints, or relationships. The schema titles already convey most of this, so the description contributes minimal semantic value beyond what an agent would infer from the property names.

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 ('Validate'), names the resource ('promote URL + text'), and positions it before create/launch, which clearly separates it from siblings like create_ad and launch_ad. 'Surfaces platform errors' further clarifies its diagnostic role. The phrase 'promote URL' is slightly jargon-heavy, but the overall intent is unmistakable.

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?

'Before create/launch' explicitly signals the intended lifecycle phase and implies the tool is a preflight check. It does not explicitly name alternative sibling tools or say when not to use it, so it falls short of full exclusion guidance, but the timing context is clear.

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