api_render_textRender a JS-heavy page in a real browser and return the visible text. ?url= [HTTP x402 price: $0.015]
| Name | Required | Description | Default |
|---|---|---|---|
| params | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Input schema / properties / params / additionalPropertiesRemoved value: -trueInput schema / properties / params / propertiesAdded value: +{
+ "url": {
+ "anyOf": [
+ {
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "default": null
+ }
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the behavioral burden. It discloses that the tool executes JavaScript in a real browser and returns only visible text, which is meaningful and goes beyond a basic HTTP fetch. It does not mention timeouts or error behavior, but the core side-effect-free behavior is clear.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The main behavior is front-loaded in a single sentence, and the trailing usage/pricing note is short. The 'HTTP x402 price' fragment is cryptic, but the overall description is economical and easy to scan.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple one-parameter read-only tool with an output schema, the description is nearly adequate. However, it lacks any guidance about sibling alternatives and leaves parameter semantics mostly to inference, so an agent may still be unsure about URL handling or when another rendering/scraping tool would be more appropriate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, and the description only adds '?url=', which minimally indicates that the URL is provided through the 'url' parameter. It does not explain expected URL format, encoding, whether http/https are required, or how the optional null value behaves, so it fails to compensate for the missing schema documentation.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb and resource: 'Render a JS-heavy page in a real browser and return the visible text.' This clearly identifies the operation and output, and it distinguishes the tool from siblings like api_screenshot, which returns images, and api_scrape, which likely returns raw HTML.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives a clear use case: pages that are JS-heavy and require a real browser to render properly. It does not explicitly name alternatives or say when not to use it, but the guidance is concrete enough for an agent to select this tool over simpler fetch or screenshot tools.
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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