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 that it returns lifecycle campaigns (not all campaigns) and their state, which is useful but does not go further to disclose pagination, limits, or response shape. It adds some value beyond annotations, meriting a middle score.

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 sentences with no filler: the first states the verb, resource, and payload fields; the second answers the core purpose. The information is front-loaded and every phrase earns its place.

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?

Given the tool's simplicity (one required parameter, one optional enum), coverage in the schema, and safety annotations, the description covers the essential context: what it returns, what state filtering it supports, and what question it answers. It could mention pagination or a distinction from metrics, but nothing critical is missing.

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 parameters (_apiKey and _region) are already fully documented with types, enums, and defaults. The description does not add anything about the parameters, such as how region selection affects results, so it does not elevate above the baseline.

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 ('Return') and resource ('Customer.io lifecycle campaigns'), lists exactly what fields are included (IDs, names, state, trigger configuration, actions, tags, timestamps), and states the question it answers (which automations exist and their state). It is immediately distinguishable from siblings like cio_campaign_metrics, cio_list_messages, and cio_list_segments.

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 its use case ('Answers which automations exist and whether they are running, drafted, or stopped'), but it does not explicitly state when to prefer this over sibling tools or name any alternatives. There is no when-not guidance, leaving the agent to infer the distinction.

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