Type into an element

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

The annotations only declare readOnlyHint=false, so the description usefully adds that typing uses real per-character key events rather than setting a value directly. It does not disclose whether existing text is cleared, whether the element must be visible or focusable, or what happens on failure.

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 efficient sentence with the action and mechanism front-loaded. Every phrase contributes to understanding what the tool does.

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 simple text-entry tool with fully described parameters and no output schema, the description is largely complete. It omits one potentially important behavioral detail, whether typing appends to or replaces existing field content, but otherwise provides enough context to invoke it 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?

Schema description coverage is 100%, so all three parameters are already documented. The description reinforces that selector identifies the element and text is what gets typed, but it adds no additional semantics beyond the schema, particularly for the context parameter.

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 verb and resource: focus an element matching a CSS selector and type text. The phrase 'real per-character key events' clarifies the mechanism, but it does not explicitly distinguish this tool from siblings such as browser_press_key or browser_fill_login.

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 explains how typing is performed but gives no guidance on when to use this tool versus alternatives like browser_press_key or browser_fill_login. An agent must infer its role from the operation alone.

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