Add labels to a VWO campaign

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

The description states that labels are 'organisational only and do not affect what visitors see,' which adds useful context beyond the annotations. Annotations already indicate readOnlyHint=false and destructiveHint=false, so the description complements them without contradiction.

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 two concise sentences: first explains the purpose, second gives a key prerequisite. No wasted words.

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 complexity (4 params, one is a free-form object) and no output schema, the description provides essential context (prerequisite calls) and references external docs for the body. It could mention the response format, but overall it is fairly complete.

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 schema already describes each parameter well. The description only adds a general hint about using vwo_list_labels for valid ids but doesn't elaborate on parameter meaning beyond what the schema provides. Thus, baseline 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 action 'Apply one or more existing labels to a VWO campaign' using a specific verb and resource. It also clarifies that labels are organizational only, distinguishing this from other labeling operations like vwo_list_campaign_labels or vwo_delete_campaign_label.

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?

It explicitly provides a prerequisite: 'Call vwo_list_labels first to get valid label ids.' While it doesn't mention when not to use this tool, the clear instruction helps the agent avoid errors. It could be improved by noting that this is only for adding labels, not modifying or removing them.

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