assert_element_count

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

With no annotations, the description carries the disclosure burden. It clearly communicates that the tool compares a selector match count against an expected count, but it does not state the failure behavior, whether it waits for the count, or whether hidden elements are included. The core behavior is present, but important assertion semantics are left to inference.

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, front-loaded sentence with no filler. Every word contributes to defining the operation, so it is appropriately concise given the tool's simple nature.

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 is simple, but without annotations or an output schema the description leaves gaps: the accepted values for 'by' and the failure/timeout behavior are unspecified. An agent could likely call the tool correctly using defaults, but would be guessing on edge cases such as non-CSS locators.

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 compensate for the schema's silence. It adds only minimal context: that selector identifies elements and expected_count is the number they should match. The 'by' parameter is completely undocumented, leaving the locator strategy ambiguous.

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 operation: assert that the count of elements matching a selector equals an expected value. The 'number of elements' phrasing clearly separates it from sibling assertion tools like assert_text or assert_element_visible, which check different conditions.

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 gives no guidance about when to choose this tool over the many sibling assertions/query tools, nor does it mention any exclusions. The intended use case is only implicit in the tool name and one-line description.

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