OnPage.dev

Layout and first screen

layout

Read-onlyIdempotent

What visitors and crawlers see on every screen size. Pick with mode: render = First screen on phone, tablet and desktop in a real browser, and what crawlers without JavaScript get (default). Needs url. probe = A measurement script to run in the user's own browser tool. analyze = Analyse the results of that script. Needs url, results.

Input Schema

Name	Required	Description
`url`	No	Full address of the page, for example https://example.com/pricing.
`mode`	No	Default render.
`no_js`	No	Optional: the probe result with JavaScript turned off, for an exact comparison.
`detail`	No	brief = short summary.
`results`	No	One probe result per viewport, each with device set to phone, tablet or desktop.
`memory_key`	No	site_memory key, records this call.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 14, 2026

removedOutput schema / description

Removed value: -"The result as structured data; fields depend on mode."

Changed2 schema fields changedOct 13, 2026

changedInput schema / properties / detail / description

Previous value: -"brief returns a short summary, default full."New value: +"brief = short summary."

changedInput schema / properties / memory_key / description

Previous value: -"Optional site_memory key, to record this call in the site memory."New value: +"site_memory key, records this call."

Changed1 schema field changedOct 12, 2026

addedInput schema / properties / detail

Added value: +{
+  "description": "brief returns a short summary, default full.",
+  "enum": [
+    "full",
+    "brief"
+  ],
+  "type": "string"
+}

Changed3 schema fields changedOct 12, 2026

addedInput schema / properties / memory_key

Added value: +{
+  "description": "Optional site_memory key, to record this call in the site memory.",
+  "maxLength": 80,
+  "type": "string"
+}

changedInput schema / properties / mode / description

Previous value: -"Default analyze."New value: +"Default render."

changedInput schema / properties / mode / enum

Previous value: -[
-  "analyze",
-  "probe"
-]New value: +[
+  "render",
+  "probe",
+  "analyze"
+]

AddedOct 12, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, and the description adds real context: render uses "a real browser" and captures "what crawlers without JavaScript get," while probe delegates execution to the user's browser. That materially explains execution model beyond the structured safety hints.

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?

Front-loaded purpose sentence followed by a compact per-mode breakdown; every clause carries information. It is telegraphic and slightly dense, but there is no filler to trim.

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?

With an output schema present, return values need not be explained, and the description covers mode semantics and required inputs for a 6-parameter tool. The main residual gap is that it does not call out optional params (no_js, detail, memory_key) or differentiate from siblings, though the schema fills those in.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description goes further by explaining what each mode value actually produces and which params each mode requires. It leaves no_js, detail, and memory_key to the schema, but those are already well documented there.

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?

The description states the resource concretely: "What visitors and crawlers see on every screen size," and then describes each mode's distinct output (first-screen rendering vs. a probe script vs. analysis). This lets an agent distinguish the three behaviors. It never positions itself against sibling tools like content or technical, so it stops short of a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit mode-selection guidance ("Pick with mode"), marks render as the default, and names the required inputs per mode ("Needs url," "Needs url, results"). It does not say when to prefer this tool over sibling tools such as content or scan_page, which keeps it below a 5.

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

All OnPage.dev tools Inspect

Try in Browser

Context Every Agent Can ShareAgents share what they learn, hand off work, and keep it when you switch models. Start with 5 GB free.fulcradynamics.comAd

Glama MCP Gateway

Add one secure layer between your agents and this server.