viewport_set_layout

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

Annotations already flag destructiveHint=true, indicating the operation modifies state. The description does not add behavioral details beyond that, such as whether the change is persistent or affects all viewports. Since annotations cover the safety profile, the description adds minimal extra context, justifying a 3.

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 brief and front-loaded, presenting the purpose and options in two short lines. The bilingual repetition is slightly redundant but not wasteful. It earns a 4 for efficiency, with a minor deduction for duplicated content across languages.

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 single-parameter tool with no output schema, the description is largely complete. It names all possible layout values and the action. It does not mention return values or side effects, but given the simplicity and the annotation flags, this is acceptable. A 4 reflects that the essential calling context is present.

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?

While the schema covers the parameter with 100% description (just 'Layout name.'), the enum values like '2h' and '2v' are cryptic. The tool description maps them to 'horizontal split' and 'vertical split', adding meaningful semantics beyond the schema. It also lists all valid options in plain language, which helps the agent understand each value.

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 tool switches the viewport layout and enumerates the specific layouts (single, horizontal split, vertical split, three, quad, maximize). It is specific about the action and resource, and distinguishes itself from sibling viewport tools like viewport_set_view or viewport_zoom_extents by focusing solely on layout arrangement.

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 conveys the tool's purpose clearly, so an agent can infer when to use it (when a layout change is needed). It does not explicitly exclude alternatives or mention when not to use it, but the context is unambiguous given the tool name and enumeration of options. There is no misleading guidance.

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