List ad sources

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

The annotation readOnlyHint=true already indicates a safe read operation. The description adds that results include ad source IDs, which is useful return context. However, it does not disclose pagination behavior, ordering, or any other behavioral nuances, but the schema covers pagination parameters, and the tool is a simple listing operation.

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 a single, well-structured sentence that is front-loaded with the verb and resource, followed by the scope and return details. There is no redundant or filler content, making it highly efficient.

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 simple list tool with two optional parameters, no output schema, and good annotations, the description is nearly complete. It states the purpose, the scope ('available to the AdMob account'), and the key return detail (ad source IDs). It lacks explicit mention of pagination, but the schema covers that, so the overall information is adequate.

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%, with both pageSize and pageToken having clear structural descriptions. The tool description does not add any additional meaning to the parameters, but since the schema fully documents them, a baseline score of 3 is appropriate.

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 clearly states the tool lists mediation ad sources (ad networks) available to the AdMob account, with their ad source IDs. It uses a specific verb ('Lists') and resource ('mediation ad sources'), and the mention of ad networks and ad source IDs distinguishes it from sibling list tools like list_accounts or list_ad_units.

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 implies this tool is for retrieving ad sources from the AdMob account, but it does not explicitly state when to use it over alternatives or mention any exclusions. While the context clearly differentiates it from other list tools, no direct 'when to use' guidance is provided.

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