open_viewer

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

With no annotations provided, the description carries the behavioral disclosure burden. It states the side effect of opening a browser viewer, the dependency on a previously rendered model, and the rotate/zoom/pan controls. It does not mention what happens if no model has been rendered yet, but the core behavior is transparent.

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 front-load the action and then add the relevant behavioral detail. There is no redundant wording, and every clause contributes useful information about what the tool does and what the user can do in the viewer.

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, zero-parameter browser-viewer tool, the description covers the action, the content shown, and the available interactions. The only notable omission is an explicit statement about prerequisites or error behavior when no model has previously been rendered.

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 input schema has zero properties, so there are no parameter semantics to document. The description reinforces the no-input nature by referring to 'the most recently rendered model' rather than any user-supplied argument, which earns the baseline score for a zero-parameter tool.

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 opens with a specific verb and resource: 'Open the interactive 3D viewer in the browser.' It then clarifies what the viewer shows and how the user can interact. This clearly distinguishes it from rendering/export sibling tools by focusing on browser-based viewing rather than producing render outputs.

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: the viewer shows 'the most recently rendered model,' so an agent can infer this tool is used after a render operation to inspect the result. It does not explicitly name alternatives or state when not to use it, but the context is sufficient for a zero-parameter tool.

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