web-ui-tester

Wait for condition

browser_wait_for

Wait for specified text to appear, disappear, or a CSS selector to become visible, ensuring UI tests sync after async updates.

Instructions

Waits for text to appear, text to disappear, or a selector to become visible. Use after actions that trigger async updates.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "sessionId": "<sessionId>"
    },
    "name": "browser_wait_for"
  }
}

Input Schema

Name	Required	Description
`text`	No	Wait until this text is visible.
`selector`	No	Wait until this CSS selector is visible.
`textGone`	No	Wait until this text is gone.
`sessionId`	Yes	Session id returned by browser_start.
`timeoutMs`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 24, 2026

TDQS

A3.6/5.0

Behavior2/5

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

The description explains the waiting behavior but does not disclose what happens on timeout, the default timeout, or whether it returns a success/failure signal. The annotations (readOnlyHint: false) imply possible side effects, yet the description gives no insight into side effects or error handling, leaving a significant transparency gap.

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 two sentences long, front-loads the core action, and has no filler. Every word contributes to understanding the tool's purpose and usage context.

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 multiple optional conditions, a timeout parameter, and no output schema, the description is incomplete. It omits how conditions interact, the default timeout, and what the tool returns or does on failure. This leaves agents guessing about critical invocation details.

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

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema covers 80% of parameters with descriptions. The description adds the semantic mapping of text, textGone, and selector to the three waiting modes, but it fails to state that exactly one condition should be provided, which is a critical constraint. It does not go beyond the schema's basic definitions.

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

Purpose5/5

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

The description clearly states the tool waits for one of three specific conditions (text appear, text disappear, selector visible), making the verb and resource explicit. It is easily distinguished from sibling tools like browser_snapshot or browser_query, which check state rather than wait.

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

Usage Guidelines4/5

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

The description says 'Use after actions that trigger async updates,' providing clear context for when to invoke the tool. It does not explicitly name alternatives or state when not to use it, but the guidance is actionable and sufficient for most agents.

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