win_set_control_text

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

Annotations already indicate the tool mutates state (readOnlyHint=false) and is idempotent. The description adds valuable behavioral detail: the underlying mechanism (WM_SETTEXT), that it works without focus, and that it operates on background windows. It also documents the return format. No contradiction with annotations.

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 concise, well-structured with Args/Returns sections, and front-loaded with the core purpose. Every sentence adds value—the example with Notepad and the focus-free behavior are relevant and not wasteful.

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 mutation tool with nested parameters and an output schema, the description provides enough context: it explains the target, the method, the source of hwnd, and the return JSON. It could mention failure cases or platform limitations, but overall it is sufficiently complete for an agent to invoke correctly.

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 description summarizes params as 'target control by hwnd (preferred) or title, plus text', clarifying the primary identifier and required input. It also points to list_child_windows as the source for hwnd. Although the schema covers detailed property descriptions, the description adds practical guidance and preference, partially compensating for the low schema_description_coverage.

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: 'Set a control's text directly via WM_SETTEXT'. It identifies the target resource (a control identified by hwnd) and differentiates from sibling tools like win_send_keys by emphasizing 'reliable, no focus needed' and that it works on background windows.

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 concrete usage context: pass a control hwnd (from list_child_windows) to modify text without bringing the window forward. It does not explicitly name alternative tools or state when not to use it, so it lacks a clear exclusion clause.

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