Preselect split direction

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

Since no annotations are provided, the description carries the full disclosure burden. It states the behavioral effect: the next opened window will occupy the chosen side. This is clear and direct. It does not mention whether the preselect resets after use or if it overrides prior settings, but for a simple one-shot state setter, this level of transparency is adequate. The example reinforces the behavior. No contradictions.

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 long and front-loaded with the core purpose. The first sentence states the action and effect; the second provides a concrete usage example. Every word earns its place. There is no redundant phrasing or fluff.

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 a single enum parameter and no output schema, the description is complete. It explains what the tool does, when to use it (before opening a window), and provides an example. There is no missing information an agent would need to invoke it correctly. The simplicity of the tool does not demand more.

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 defines the 'direction' parameter as an enum with values 'l', 'r', 'u', 'd' but provides no descriptions. The description adds semantic meaning by giving an example: 'preselect 'r' then open a terminal to get a right-hand split,' which clarifies that 'r' means right. It implicitly suggests the other letters map to left, up, down. While not exhaustive, it compensates for the 0% schema coverage adequately for a simple 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 clearly states the tool's purpose: 'Choose which side of the focused tile the NEXT opened window will occupy.' This is specific about the verb (choose), resource (focused tile), and effect (next opened window placement). It distinguishes itself from siblings like open_window_split (which actually opens a split) and layout_mode (which sets layout type). The purpose is unambiguous and directly tied to the tool's name and title.

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 gives explicit usage guidance: 'Chain with open_window for split layouts' and provides a concrete example: 'preselect 'r' then open a terminal to get a right-hand split.' This tells the agent exactly when to use the tool (before opening a window) and how it fits into a workflow. While it doesn't explicitly list alternatives, the chaining instruction makes the intended context clear and actionable.

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