browser_exists

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

With no annotations, the description carries the full burden. It discloses the return format (JSON envelope reporting existence) but does not explicitly state that the operation is side-effect-free, whether it waits for the element, or any timing behavior. This is a modest disclosure for a read-like operation.

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 and structured with args and returns clearly listed. It is efficient with no wasted words, though it could be slightly more detailed without becoming verbose.

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 existence check, the description provides essential information: purpose, parameters, and return shape. However, it omits details like whether the tool waits for the element, what 'present' means in edge cases, or any error behavior. Given the low complexity, this is adequate but not fully complete.

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 adds meaningful context for both parameters: serialno is explicitly tied to list_devices, and selector is identified as a CSS selector. Since schema coverage is 0%, this compensates well, though it could elaborate further on selector syntax or expected value formats.

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 ('Check') and resource ('whether an element is present'), making the primary purpose clear. However, it does not explicitly differentiate from related siblings like browser_state or mobile_dump_hierarchy, so it falls 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?

There is no guidance on when to use this tool versus alternatives. It does not state typical usage scenarios, exclusion conditions, or reference any sibling tools. Usage context must be inferred by the agent from the verb 'check'.

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