count

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

With no annotations and no output schema, the description carries full behavioral burden, yet 'element count' discloses nothing about the return value (an integer), how counts are computed, or any edge cases such as zero matches. No mutation, auth, or rate-limit context is given.

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 extremely short, but this reflects under-specification rather than efficient conciseness. Two words do not earn their place because they fail to communicate anything beyond the tool name.

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 tool with one required parameter, no parameter documentation, no output schema, and no annotations, the description is completely inadequate. It omits the selector format and the return value, both essential for correct invocation.

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 single required parameter 'selector' has 0% schema description coverage, and the description provides no meaning for it. It does not clarify whether the selector is a CSS selector, XPath, text, or some custom syntax, leaving the agent to guess.

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 phrase 'element count' is a fragment that essentially restates the tool name rather than stating a clear verb+resource relationship. It hints that the tool counts elements, but provides no full sentence or scope, and does not differentiate from siblings like get_text, exists, or get.

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 such as get, exists, is_visible, or get_text. No context, prerequisites, or exclusions are provided.

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