Start preview

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

With no annotations provided, the description must fully disclose behavioral traits. It only states that a preview is started and a URL returned, omitting details like whether this is asynchronous, has side effects on existing previews, requires authentication, or has rate limits. There is no contradiction, but the description adds minimal behavioral context beyond the basic action.

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 sentences and front-loads the core action. The second sentence, 'Give the URL to the user,' is arguably redundant with 'return its URL' but adds a directive and is not harmful. Overall, it is concise and easy to parse.

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 tool with no annotations, no output schema, and an undocumented parameter, the description is insufficient. It fails to explain the input parameter, lacks usage context, and does not clarify behavioral expectations. An agent cannot reliably know what to pass or what to expect beyond a URL.

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 0%, so the description must explain the 'app' parameter. It does not. The agent is left to guess whether 'app' refers to an app ID, name, or path. This is a critical gap for a required single-parameter tool; the description provides no semantic value for the parameter.

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 specific verb ('Start'), resource ('live dev preview'), and expected output ('return its URL'). It clearly differentiates this tool from siblings like stop_preview and share_preview by implying it initiates a new preview, though it doesn't name alternatives. The core purpose is unambiguous.

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?

No guidance is given about when to use this tool versus alternatives such as share_preview or stop_preview. There is no mention of prerequisites, typical workflow, or conditions that would favor this tool. The agent must infer that starting a preview is a first step, which is not explicit.

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