Create a new window

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

No annotations are provided, so the description carries the full burden. It states the primary action but does not disclose side effects (e.g., whether the new window becomes active), error behavior, or any other behavioral traits. The description is superficial and does not help the agent anticipate consequences beyond 'create a window'.

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, front-loaded with the core action. The phrase 'useful for side-by-side collaboration' is somewhat extraneous but not harmful. It is concise and to the point, with no redundant repetition of the name.

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?

Given the tool's simplicity, 100% schema coverage, and no output schema, the description is adequate but lacks important context. It does not mention what happens after creation (e.g., window activation), how it interacts with other tools, or any limitations. There are clear gaps, but not severe enough for a lower score.

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 coverage is 100%, with every parameter described in the schema (e.g., target as 'Target session (or window)...' and command as 'Optional command to run when the window starts'). The description adds no additional parameter meaning; it merely reiterates 'target session'. Baseline 3 is appropriate because the schema does the heavy lifting.

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: 'Create a window in a target session', which is specific and matches the tool name. It distinguishes from siblings like tmux_new_session by focusing on windows, though it does not explicitly name alternatives. The 'side-by-side collaboration' phrase adds a use case but not differentiation.

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 implies usage for creating windows in existing sessions, especially for side-by-side collaboration. However, it provides no explicit when-to-use vs. alternatives, no exclusions, and no mention of prerequisites like whether the target session must exist. This is minimal guidance.

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