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

Annotations already declare a non-read-only, non-destructive, open-world write; the description adds real value by disclosing the return ('extension result and available identifier') and failure mode ('validation/platform error'). It does not mention that creation mutates the shared asset library or any account-access requirements.

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?

Three short sentences, front-loaded with the action, then the outcome, then the scoping caveat. No 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?

No output schema exists, and the description usefully covers return values and errors, so that gap is closed. However, with three parameters at 0% schema coverage and no explanation of the required image_library_id, an agent still lacks enough to populate the call confidently.

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%, so the description carries the full burden — but 'using the supplied fields' adds nothing. Nothing explains that image_library_id is a required reference to a previously uploaded image asset or what domain_name/business_name constrain, despite the 25/50 character limits.

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 and resource ('Create a business logo extension') scoped to the Microsoft Ads asset library. This clearly separates it from the Google counterpart (create_google_business_logo_extension) and from the various Microsoft callout/image/price/sitelink siblings.

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?

Adds a valuable routing note: 'Attaching the extension to a campaign is a separate operation,' which steers the agent away from expecting campaign association here. It doesn't state prerequisites such as needing an existing image library asset, and gives no explicit when-not guidance.

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