Like read_url but returns only the page description + the first ~600 characters of the markdown (title + word count + a truncation flag) — a cheap way to check a page's relevance before pulling the full text. Free.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | absolute http(s) URL of a publicly reachable HTML page |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries full behavioral disclosure burden. It discloses that the tool is cheap/free, returns truncated content, and includes a truncation flag. It does not mention error behavior or rate limits, but for a simple preview tool this is largely sufficient.
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?
Two sentences with no wasted words. It front-loads the 'like read_url' comparison, immediately establishes the output scope, and ends with a usage hint. Every sentence earns its place.
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?
Given no output schema and low complexity (1 param), the description is quite complete: it specifies what the preview contains, when to use it, and indicates cost. Minor omission of error/edge-case behavior, but overall sufficient for the tool's simplicity.
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 coverage is 100% (only one parameter, url, with a clear description). The description adds no additional meaning beyond what the schema provides for the parameter. Baseline 3 is appropriate.
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 clearly states it returns a preview (page description + first ~600 characters of markdown with title, word count, truncation flag) of a URL. It explicitly distinguishes itself from sibling read_url by highlighting the reduced scope, which helps an agent differentiate between tools.
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 explicitly says it is 'a cheap way to check a page's relevance before pulling the full text.' This provides clear guidance on when to use this tool (cheap relevance check) vs. alternatives like read_url (full text). It also mentions 'Free', offering a cost hint.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Tools have distinct purposes (read full, read preview, render PDF, render preview, render screenshot). However, render_preview is a discovery stub for both PDF and screenshot, which could cause some ambiguity about which specific render tool it relates to.
Consistent verb_noun pattern with underscores: read_url, read_url_preview, render_pdf, render_preview, render_screenshot. Naming clearly indicates whether the tool reads text or renders visual output.
Five tools is appropriate for a web page reader that offers both text extraction and rendering capabilities. The set is neither too sparse nor overloaded.
The core read tools cover the primary purpose of fetching and converting URLs to markdown. The rendering tools are included but currently non-functional (return 503 or x402), leaving a gap in visual rendering capabilities. JavaScript-rendered pages are also unsupported.