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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the useful detail that creatives and performance metrics are included in the response, which is beyond the annotations. However, it doesn't disclose error behavior, return format, or other side effects. With annotations handling the main behavioral burden, a 3 is appropriate.

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 accomplish everything: the primary purpose is stated first, the included response content is mentioned, and the fallback sibling is named. There is no filler or redundancy.

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?

This is a simple single-resource getter with strong annotations and a clear required parameter. The description tells the agent what response content to expect even though there is no output schema. It lacks explicit error-handling details, but the fallback guidance covers the most likely failure case.

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 67% because platform and workspaceId are documented, while adCampaignId lacks a description but is self-explanatory from its name and the tool description. The description does not add extra parameter-level meaning beyond what the schema already provides, so the baseline of 3 fits.

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 action ('Get one ad campaign by ID'), the resource ('ad campaign'), and the included contents ('creatives and performance metrics'). It also differentiates this from the sibling list operation by emphasizing the single-ID retrieval scope.

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 gives an explicit fallback: 'If not found, use campaignstack_list_ad_campaigns to find valid IDs.' This tells the agent exactly when to switch to a sibling tool, which is strong usage guidance.

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