WebLens

fetch_webpage_pro

Fetch webpage with full JavaScript rendering using headless browser. Perfect for SPAs, React/Vue apps, and dynamic content that requires JS execution. Price: $0.006, up to 3x on bot-protected or complex sites (70% off when served from cache); an x402 payment is at least $0.004

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>"
    },
    "name": "fetch_webpage_pro"
  }
}

Input Schema

Name	Required	Description
`url`	Yes	The URL to process
`cache`	No	Serve a cached copy when one exists (cached responses are 70% off)
`timeout`	No	Request timeout in milliseconds
`waitFor`	No	CSS selector to wait for (Pro tier only)
`cacheTtl`	No	How long to cache this response, in seconds

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 13, 2026
- changedInput schema / properties / url / example
```
Previous value: -"https://app.example.com"New value: +"https://example.com"
```
- changedInput schema / properties / waitFor / example
```
Previous value: -".content"New value: +"p"
```

Changed10 schema fields changedOct 13, 2026

addedInput schema / properties / cache

Added value: +{
+  "default": true,
+  "description": "Serve a cached copy when one exists (cached responses are 70% off)",
+  "example": true,
+  "type": "boolean"
+}

addedInput schema / properties / cacheTtl

Added value: +{
+  "default": 3600,
+  "description": "How long to cache this response, in seconds",
+  "maximum": 86400,
+  "minimum": 60,
+  "type": "number"
+}

addedInput schema / properties / timeout / default
```
Added value: +10000
```

changedInput schema / properties / timeout / description

Previous value: -"Request timeout in ms (default 15000)"New value: +"Request timeout in milliseconds"

addedInput schema / properties / timeout / example
```
Added value: +15000
```

changedInput schema / properties / url / description

Previous value: -"The URL to fetch"New value: +"The URL to process"

addedInput schema / properties / url / example
```
Added value: +"https://app.example.com"
```
addedInput schema / properties / url / format
```
Added value: +"uri"
```

changedInput schema / properties / waitFor / description

Previous value: -"CSS selector to wait for before capturing content (e.g. \".content\")"New value: +"CSS selector to wait for (Pro tier only)"

addedInput schema / properties / waitFor / example
```
Added value: +".content"
```

First observedAug 4, 2026

TDQS

A3.6/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does disclose a genuinely actionable trait: a per-call cost model ($0.006 base, up to 3x on bot-protected sites, 70% cache discount, x402 minimum). This lets an agent reason about budget before calling. It still omits what the response contains (raw HTML vs. extracted text) and failure/timeout behavior, so it is not complete.

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?

Purpose is front-loaded in the first clause, followed by a targeted use-case list and then pricing. Every sentence carries information an agent can act on; the pricing sentence is dense but earns its place for cost-aware routing.

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

Completeness3/5

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

For a 5-parameter tool with no annotations and no output schema, the description covers purpose and cost but says nothing about the return format or what happens on render failure/timeout. The schema covers inputs fully, but the agent is left guessing at the output contract.

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% – every parameter including cache, timeout, waitFor, and cacheTtl is documented in the schema itself. The description adds no parameter-level syntax or constraint detail beyond reinforcing the cache discount already stated in the cache property. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Fetch webpage') and immediately distinguishes itself by mechanism ('full JavaScript rendering using headless browser'), which is the key differentiator from plain fetch siblings. However, it never names or contrasts with fetch_webpage or fetch_resilient, so the agent must infer which sibling to prefer.

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?

'Perfect for SPAs, React/Vue apps, and dynamic content that requires JS execution' implies when this tool is the right choice, giving usable context. But there are no explicit exclusions or named alternatives (e.g. 'use fetch_webpage for static HTML'), leaving the routing decision to inference.

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

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