Press a key

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

Annotations already declare readOnlyHint=false, idempotentHint=false, openWorldHint=true, and destructiveHint=false, so the safety profile is known. The description adds the useful detail that this is a browser/Playwright-level key event rather than an application command, but it never states the prerequisite that a page must be open and focused, nor that key events can mutate arbitrary app state.

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 sentence with the action and the accepted syntax front-loaded and examples trailing as illustration. Nothing is repeated from structured fields and no wording is wasted.

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 one-parameter, annotation-covered, no-output-schema tool, the definition is essentially complete: the caller knows the resource, the format, and example values. The remaining gap is the environmental prerequisite (an open, focused page), which an agent may not assume.

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 0% — the schema only says 'string, minLength 1' — so the description must carry the load, and it does: Playwright syntax plus concrete examples ('Enter', 'Escape', 'Tab', 'Control+Z', 'Control+B') tell the caller exactly what format to pass, including modifier combos. It falls just short of a full 5 because it doesn't state whether key names are case-sensitive or that only one combo per call is allowed.

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 gives a specific verb+resource ('Press a keyboard key or combo in the browser') and enumerates representative inputs, so the action is unambiguous. It stops short of explicitly distinguishing itself from siblings like gsites_type or gsites_click, leaving that separation to inference.

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?

Usage is only implied: an agent can infer this is for keyboard interaction rather than mouse clicks or text entry, but there is no explicit 'use this instead of gsites_type when…' guidance. The example keys are helpful for callers but are format guidance, not when/when-not guidance.

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