Browser type

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the action ('type or fill') and does not reveal whether it replaces existing text, whether the element must be visible, or any side effects such as triggering input events. This lacks the context needed for a mutation tool.

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 and front-loaded with the core action, which is concise. However, it is under-specified for a tool with four parameters and two distinct behaviors ('type' vs 'fill'), making it more vague than appropriately concise.

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?

The tool has 4 parameters, no output schema, and no annotations, yet the description explains neither the return value nor the difference between typing and filling. Sibling tools like browser_click and browser_press_key highlight that this tool's behavior is nuanced, and the description does not cover that nuance.

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 0%, so the description must explain parameters, but it only implies 'text' and 'element' without addressing session_id, selector format, or the 'fill' boolean. This leaves the agent reliant on parameter names alone, which is insufficient.

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 ('Type or fill text') and the resource ('an element in a browser debug session page'), which distinguishes it from sibling tools like browser_click or browser_press_key. However, it does not explicitly name any alternative or differentiate itself from browser_select_option or browser_evaluate, so it falls just short of a 5.

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 provides no guidance on when to use this tool versus alternatives such as browser_press_key or browser_select_option. There is no mention of prerequisites, when typing is preferred over filling, or which scenarios call for the 'fill' parameter.

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