Skip to main content
Glama

assert_element_visible

Verify an element is visible on a web page using a CSS selector, with an optional timeout to confirm UI state during automated browser testing.

Instructions

Assert an element is visible on the page.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
byNocss
timeoutNo
selectorYes

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. First observedv1.0.0

TDQS

C2.7/5.0
Behavior2/5

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 states the assertion but does not disclose what happens on failure, whether the tool waits or retries up to the timeout, or whether it has side effects. The timeout parameter implies waiting behavior, but the description never confirms it.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single focused sentence with no redundant or filler content. Every word adds meaning, and the core subject and action are front-loaded. It is appropriately concise for a simple assertion tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no annotations and no output schema, the description is not sufficiently complete. It omits failure behavior, timeout semantics, selector strategy defaults, and how it differs from similar visibility-related tools. An agent needs more context to invoke it reliably in an assertion workflow.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

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 lack of parameter documentation. It does not explain selector, by, or timeout beyond the bare schema property names and defaults. The agent gets no additional meaning about how to construct the selector, what by values are accepted, or how timeout affects execution.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'Assert an element is visible on the page.' It clearly conveys the core action and target. However, it does not distinguish this from closely related siblings like is_displayed or wait_for_element, so it falls just short of a top score.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives. It does not mention is_displayed, assert_element_not_visible, wait_for_element, or explain that this is a test assertion that fails the test rather than returning a boolean. The agent is left to infer usage from the tool name alone.

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

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/hakanngul/testfly-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server