Spider MCP Server

spider_ai_browser

Automate browser actions by describing tasks in natural language. Spider follows your instructions to click buttons, fill forms, and navigate pages.

Instructions

AI-powered browser automation using natural language. Describe what to do and Spider automates the browser — click buttons, fill forms, navigate pages. Requires an active AI subscription (https://spider.cloud/ai/pricing).

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": {
      "url": "<url>",
      "prompt": "<prompt>"
    },
    "name": "spider_ai_browser"
  }
}

Input Schema

Name	Required	Description
`url`	Yes	Starting URL
`prompt`	Yes	Automation instructions (e.g. 'Click the Sign In button, enter email, submit the form')
`cookies`	No	HTTP cookies
`proxy_enabled`	No	Enable premium proxies
`return_format`	No	Output format. Default: raw

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.2Jul 6, 2026

TDQS

B3.4/5.0

Behavior2/5

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

With no annotations, the description must disclose behavioral traits. It reveals the requirement for an AI subscription, but does not cover other aspects such as session management, error handling, rate limits, or whether automation is headless. The description is incomplete for a complex tool.

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?

Two sentences, both front-loaded with key information. The first explains the tool's purpose, the second adds the subscription requirement. No filler or redundant content.

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 output schema and moderate complexity (5 params, natural language interpretation), the description is insufficient. It lacks explanation of how the AI interprets prompts, what the return format represents, or behavioral constraints like session lifetime. The sibling tools suggest lower-level alternatives exist, but the description does not clarify when to use this aggregate tool.

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 input schema has 100% parameter description coverage, so baseline is 3. The description adds no extra meaning beyond what the schema provides, such as clarifying the role of cookies or proxy_enabled in the automation context.

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 it performs AI-powered browser automation using natural language, mentioning specific actions like clicking buttons, filling forms, and navigating pages. This distinguishes it from sibling tools such as spider_ai_crawl (crawling) and lower-level browser tools like spider_browser_click, which are step-by-step.

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 implies usage when wanting to automate browser actions via natural language, and mentions a required AI subscription. However, it does not explicitly state when to use this tool versus alternatives (e.g., lower-level browser tools) or when not to use it.

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