Spider MCP Server

spider_browser_wait_for

Wait for a CSS selector to appear in the DOM or for page navigation to finish, ensuring dynamic content is fully loaded before proceeding.

Instructions

Wait for a condition on the page. Use after navigation or actions that trigger dynamic content loading.

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": {
      "session_id": "<session_id>"
    },
    "name": "spider_browser_wait_for"
  }
}

Input Schema

Name	Required	Description
`timeout`	No	Max wait time in ms. Default: 30000
`selector`	No	CSS selector to wait for (element must appear in DOM)
`navigation`	No	Wait for the next navigation to complete
`session_id`	Yes	Session ID from spider_browser_open

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.2Jul 6, 2026

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the full burden of disclosing behavior. It states the tool waits for a condition but omits critical details like timeout expiration behavior (error or retry), whether it blocks, and what it returns. This is insufficient for an agent to predict side effects.

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

Conciseness4/5

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

The description is two sentences that are clear and front-loaded. The first sentence states the purpose, the second provides usage context. It is concise but not overly abbreviated, earning a score of 4.

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?

Given the tool's complexity (waiting for dynamic conditions) and the absence of an output schema, the description should explain return behavior, timeout handling, and required session context. It does not, leaving the agent uninformed about key aspects.

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?

All four parameters have descriptions in the input schema (100% coverage). The description adds no extra parameter meaning beyond the schema, so a baseline score of 3 is appropriate.

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 a condition on the page, which is a specific action distinct from sibling tools like clicking, navigating, or scraping. It also provides context on when to use it (after navigation or dynamic content actions).

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

Usage Guidelines3/5

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

The description mentions using the tool after navigation or actions that trigger dynamic content, but does not explicitly specify when not to use it or suggest alternatives. This leaves some ambiguity for an AI agent deciding between wait_for and other tools.

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