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

Annotations already declare readOnlyHint=true, and the description reinforces this with the GET endpoint. It adds the API path context but does not disclose error behavior, auth requirements, or response format, so it adds only modest value beyond the annotation.

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 efficient sentence with the core purpose front-loaded and the API path appended for reference. There is no redundant or misleading content.

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 one-parameter read-only lookup with complete schema coverage and supporting annotations, the description is sufficient. Nothing needed to invoke the tool correctly is missing, and the API endpoint provides useful context.

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 coverage is 100%, so the single parameter campaign_id is already fully documented in the schema. The description adds no additional meaning beyond the endpoint placeholder, which matches the baseline for high schema coverage.

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 precise action and resource: 'Get a single campaign by id.' It clearly differentiates from sibling tools like customerio_list_campaigns and customerio_get_campaign_metrics by focusing on a single campaign lookup.

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 'by id' phrasing makes the use case clear: call this when you already have a specific campaign_id and want one campaign. It does not explicitly mention alternatives like listing campaigns, but the context is sufficient for an agent to choose correctly.

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