split_pane

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

Annotations already set readOnlyHint=false and idempotentHint=false, and the description adds no behavioral context beyond the mutation implied by "split". It does not mention how size is interpreted, whether a new pane is created, or consequences for the existing layout.

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 a single sentence with no filler and is front-loaded with the action. However, it is minimal to the point of omitting almost all useful detail, so it does not earn a perfect score.

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?

With no required params and an output schema present, it need not explain return values, but it still leaves major ambiguities: what target refers to, default behavior when omitted, size units, and relationship to the current layout. The description is too thin for a tool with four optional parameters.

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% and the description adds no extra meaning for size, target, direction, or start_directory. The only hint ("horizontally or vertically") merely restates the direction enum.

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 and resource: "Split target pane horizontally or vertically". No sibling tool performs splitting, so it clearly distinguishes itself from the rest.

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 on when to use this tool versus alternatives like resize_pane or zoom_pane, nor are there any prerequisites or exclusions. The action is obvious, but the description provides no context for selection.

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