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

Annotations only provide readOnlyHint=true, so the description carries most behavioral context. It adds valuable semantics: an empty list means nothing is disapproved, not a failure, and the result includes review status plus structured reasons/affected markets. This goes beyond the annotation and helps an agent interpret results correctly.

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 front-loaded with the core purpose and each sentence adds useful context. There is minor redundancy around active Space scoping appearing in both the first and last sentences, but overall it remains appropriately sized and readable.

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 reasonably explains what the response contains: review status and structured reasons/affected markets. It also covers empty-list interpretation and Space scoping. It doesn't describe pagination or platform-specific edge cases, but for a read-only listing tool with two optional params, the coverage is solid.

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 both parameters are already well documented. The description reinforces space_id's override behavior and active Space scoping, but it adds little beyond what the schema already states and does not describe the platform parameter's behavior in detail.

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 a specific verb ('List') and clearly defines the resource: ads and keywords that are NOT serving, including disapproved, limited, or area-of-interest-only items. It further distinguishes itself from sibling tools like list_ads and list_keywords by focusing on non-serving items with review status and structured reasons/affected markets.

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 explicitly identifies the best use case: answering 'why isn't this ad running?' without paging through every ad and keyword. It also clarifies active Space scoping and points to set_active_space or space_id to change scope, though it doesn't explicitly say when to use the broader list_ads/list_keywords tools instead.

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