active_window

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

With no annotations, the description carries the full burden. It helpfully explains the returned `keys_go_to` semantics (the window under your pointer when you own the pointer) and the focus state, implying a safe read query, but it never explicitly states read-only behavior, whether it has side effects, or any conditions under which the values are unavailable.

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?

A single front-loaded sentence delivers the purpose, the meaning of the key return field, and the action guidance with no filler. Every clause earns its place.

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?

An output schema exists, so return values need not be spelled out, yet the description usefully characterizes the primary field. With zero parameters and a focused, single-condition use case, the definition is nearly complete; only explicit behavioral traits are left uncovered by the absence of annotations.

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 tool takes zero parameters, so there is nothing for the description to clarify; the baseline for a parameterless tool is 4. No parameter meaning is missing.

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 resource (the active window) and clarifies two distinct facts it reports: where keystrokes go and which window the user has focused. It is distinguishable from a plain window enumerator like list_windows, though it never explicitly contrasts itself with that sibling.

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?

"Check this before typing" gives a clear, actionable usage condition tied to the type_text/key/hold_key siblings. It stops short of naming alternatives (e.g., list_windows) or stating when not to use it, so it is context rather than full routing guidance.

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