Update a VWO campaign variation

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

Annotations already indicate write (readOnlyHint: false) and destructive (destructiveHint: true) behavior. The description adds value by explaining that changes take effect on real traffic and alter collected data, which goes beyond the annotations. No contradictions found.

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 succinct sentences that front-load the purpose and immediately convey the impact on live traffic. Every sentence earns its place without unnecessary detail.

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 complexity (5 parameters, nested body, no output schema), the description covers purpose, behavioral impact, and essential parameter guidance. It could optionally mention return value expectations, but since no output schema exists, this is acceptable. Almost 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?

With 100% schema coverage, the baseline is 3. The description adds significant meaning: it explains the body parameter's undocumented nature and provides a link, warns against guessing accountId, and advises listing endpoints for campaignId and variationId. This far exceeds schema-only information.

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 verb 'Change' and the resource 'existing variation on a VWO campaign'. It distinguishes from sibling tools like vwo_new_campaign_variation (create) and vwo_delete_campaign_variation (delete) by implying this is the update operation.

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 provides clear context by noting that changes affect live visitors and real traffic, implying caution. However, it does not explicitly state when not to use this tool or provide alternatives like creating vs. deleting variations, though the sibling tools list makes this implicit.

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