Start preview

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It only mentions starting a preview and returning the URL, but does not disclose that this may start a background process, require dependencies to be installed first, or that the preview persists until stopped. Side effects and prerequisites are not covered.

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 short sentences with zero fluff. The main purpose is front-loaded, and the instruction to give the URL to the user is an extra useful detail. Every word 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?

For a simple tool with one parameter and no output schema, the description covers the basic return value and user-facing instruction. However, it omits critical context like prerequisites (e.g., dependencies installed), whether the preview blocks or runs in the background, and that it can be stopped via stop_preview. Adequate but with clear gaps.

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?

The schema provides only a string type for 'app' with no description (coverage 0%). The description does not explain what 'app' refers to (e.g., app ID, name) or its expected format. The agent must infer that it is the app to preview, but no further guidance is given.

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 ('Start'), the resource ('a live dev preview of the app'), and the output ('return its URL'). It distinguishes itself from siblings like stop_preview and deploy by specifying 'live dev preview'.

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 purpose implies usage (for previewing during development), but the description does not explicitly state when to use this vs. deploy or how it differs from other preview-related tools. No exclusion conditions or alternative tools are mentioned, so guidance is only implicit.

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