Spider MCP Server

spider_browser_navigate

Direct a browser to a URL using an active session. Waits for the page to load completely, then returns the URL and page title.

Instructions

Navigate the browser to a URL. Waits for the page to finish loading before returning the URL and title.

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>",
      "url": "<url>"
    },
    "name": "spider_browser_navigate"
  }
}

Input Schema

Name	Required	Description	Default
`url`	Yes	URL to navigate to
`session_id`	Yes	Session ID from spider_browser_open

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.2Jul 6, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations, the description carries full burden. It discloses that the tool waits for page loading before returning, a key behavioral trait. However, it does not mention potential timeouts, errors on invalid URLs, or content restrictions. Basic transparency but incomplete.

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 extremely concise with two sentences, no wasted words, and the key action is front-loaded. Every sentence adds value.

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

Completeness4/5

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

For a simple navigation tool with two parameters and no output schema, the description covers the core operation (navigation and waiting) and return value. It is mostly complete, though missing details on error handling or timeout behavior. Overall sufficient for agent use.

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?

Schema description coverage is 100% (both parameters have clear descriptions in the schema). The tool description adds no additional meaning beyond what the schema provides, so the 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 uses a specific verb 'Navigate' and resource 'browser to a URL', clearly stating the action. It also describes the outcome (returns URL and title), distinguishing it from siblings like spider_browser_click (clicking elements) or spider_browser_open (initializing a session).

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 needing to load a new URL in the browser, but does not explicitly state when to use this tool vs alternatives like spider_browser_click or spider_browser_open. No exclusions or prerequisites are mentioned.

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