DiffiCat

Capture screenshot

capture_screenshot

Free 5 times a day per client address, no key needed. Full-page PNG of one URL at the given viewport width, returned inline when small, else as links.file to fetch with the jobToken. Call it for a one-off look at a page or a mobile-width check. Do not call it for pages a comparison job covers: get_report names their screenshots for get_screenshot. Example: { "url": "https://new.example/pricing", "viewportWidth": 375 }. Answers with jobId, jobToken, filename, url, dimensions, bytes, links.file and, on a free run, sample and allowanceRemaining.

Input Schema

TableJSON Schema

Name	Required	Description
`url`	Yes	Page to capture (full URL).
`auth`	No	HTTP basic auth for the page.
`visual`	No	Capture rules applied to both sides.
`viewportWidth`	No	Capture width in px.
`idempotencyKey`	No	Optional opaque string a retry repeats: under a prepaid balance the same value within 24 hours is not charged again and answers DUPLICATE_REQUEST with the jobId of the first call.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`url`	No
`code`	No
`bytes`	No
`error`	No
`jobId`	No
`links`	No
`region`	No
`sample`	No
`payment`	No
`filename`	No
`jobToken`	No
`imageSize`	No
`dimensions`	No
`pagesCharged`	No
`allowanceRemaining`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedOct 17, 2026

changedInput schema / properties / visual / properties / freeze / properties / clock / description

Previous value: -"Pause timers and the clock after load on both sides; a page that waits on a timer to render may stay empty."New value: +"Pause timers and the clock after load; a page that needs a timer to render may stay empty."

addedInput schema / properties / visual / properties / freeze / properties / clockSeconds

Added value: +{
+  "description": "With clock: seconds the clock runs after load before it stops (1 to 600, default 60).",
+  "maximum": 600,
+  "minimum": 1,
+  "type": "integer"
+}

changedInput schema / properties / visual / properties / masks / description

Previous value: -"CSS selectors of elements hidden on both sites before the screenshot (at most 50, each up to 200 characters). The box is kept, so the layout does not shift."New value: +"CSS selectors of elements hidden on both sites before the screenshot (at most 50, each up to 200 characters). The layout keeps its place."

Changed1 schema field changedOct 16, 2026

addedInput schema / properties / visual

Added value: +{
+  "additionalProperties": false,
+  "description": "Capture rules applied to both sides.",
+  "properties": {
+    "freeze": {
+      "additionalProperties": false,
+      "description": "Switches that stop motion before the screenshot.",
+      "properties": {
+        "animations": {
+          "description": "Stop CSS animations and transitions before the screenshot.",
+          "type": "boolean"
+        },
+        "clock": {
+          "description": "Pause timers and the clock after load on both sides; a page that waits on a timer to render may stay empty.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "masks": {
+      "description": "CSS selectors of elements hidden on both sites before the screenshot (at most 50, each up to 200 characters). The box is kept, so the layout does not shift.",
+      "items": {
+        "maxLength": 200,
+        "minLength": 1,
+        "type": "string"
+      },
+      "maxItems": 50,
+      "type": "array"
+    }
+  },
+  "type": "object"
+}

Changed2 schema fields changedOct 11, 2026

addedOutput schema / properties / imageSize

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "height": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "width": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    }
+  },
+  "required": [
+    "width",
+    "height"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / region

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "height": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "width": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "x": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "y": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    }
+  },
+  "required": [
+    "x",
+    "y",
+    "width",
+    "height"
+  ],
+  "type": "object"
+}

Changed4 schema fields changedOct 4, 2026

changedInput schema / properties / idempotencyKey / description

Previous value: -"Optional opaque string a retry repeats: under a prepaid key the same value within 24 hours is not charged again and answers DUPLICATE_REQUEST with the jobId of the first call."New value: +"Optional opaque string a retry repeats: under a prepaid balance the same value within 24 hours is not charged again and answers DUPLICATE_REQUEST with the jobId of the first call."

addedOutput schema / properties / allowanceRemaining

Added value: +{
+  "maximum": 9007199254740991,
+  "minimum": -9007199254740991,
+  "type": "integer"
+}

addedOutput schema / properties / pagesCharged

Added value: +{
+  "maximum": 9007199254740991,
+  "minimum": -9007199254740991,
+  "type": "integer"
+}

addedOutput schema / properties / sample
```
Added value: +{
+  "type": "boolean"
+}
```

Changed1 schema field changedOct 4, 2026

addedInput schema / properties / idempotencyKey

Added value: +{
+  "description": "Optional opaque string a retry repeats: under a prepaid key the same value within 24 hours is not charged again and answers DUPLICATE_REQUEST with the jobId of the first call.",
+  "maxLength": 255,
+  "minLength": 1,
+  "type": "string"
+}

Changed5 schema fields changedOct 2, 2026

removedOutput schema / properties / payment / additionalProperties
```
Removed value: -false
```

addedOutput schema / properties / payment / anyOf

Added value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "amount": {
+        "type": "string"
+      },
+      "balance": {
+        "type": "string"
+      },
+      "currency": {
+        "const": "USD",
+        "type": "string"
+      },
+      "rail": {
+        "const": "prepaid",
+        "type": "string"
+      }
+    },
+    "required": [
+      "amount",
+      "currency",
+      "rail",
+      "balance"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "properties": {
+      "allowanceRemaining": {
+        "type": "number"
+      },
+      "amount": {
+        "type": "string"
+      },
+      "currency": {
+        "const": "USD",
+        "type": "string"
+      },
+      "pagesFromAllowance": {
+        "type": "number"
+      },
+      "rail": {
+        "const": "subscription",
+        "type": "string"
+      }
+    },
+    "required": [
+      "amount",
+      "currency",
+      "rail",
+      "pagesFromAllowance",
+      "allowanceRemaining"
+    ],
+    "type": "object"
+  }
+]

removedOutput schema / properties / payment / properties

Removed value: -{
-  "amount": {
-    "type": "string"
-  },
-  "balance": {
-    "type": "string"
-  },
-  "currency": {
-    "const": "USD",
-    "type": "string"
-  },
-  "rail": {
-    "const": "prepaid",
-    "type": "string"
-  }
-}

removedOutput schema / properties / payment / required

Removed value: -[
-  "amount",
-  "currency",
-  "rail",
-  "balance"
-]

removedOutput schema / properties / payment / type
```
Removed value: -"object"
```

Changed2 schema fields changedOct 1, 2026
- addedInput schema / properties / auth / properties / password / description
```
Added value: +"Password for HTTP basic auth."
```
- addedInput schema / properties / auth / properties / username / description
```
Added value: +"Username for HTTP basic auth."
```

Changed1 schema field changedSep 29, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "bytes": {
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "code": {
+      "type": "string"
+    },
+    "dimensions": {
+      "additionalProperties": {},
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "error": {
+      "type": "string"
+    },
+    "filename": {
+      "type": "string"
+    },
+    "jobId": {
+      "type": "string"
+    },
+    "jobToken": {
+      "type": "string"
+    },
+    "links": {
+      "additionalProperties": false,
+      "properties": {
+        "file": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "file"
+      ],
+      "type": "object"
+    },
+    "payment": {
+      "additionalProperties": false,
+      "properties": {
+        "amount": {
+          "type": "string"
+        },
+        "balance": {
+          "type": "string"
+        },
+        "currency": {
+          "const": "USD",
+          "type": "string"
+        },
+        "rail": {
+          "const": "prepaid",
+          "type": "string"
+        }
+      },
+      "required": [
+        "amount",
+        "currency",
+        "rail",
+        "balance"
+      ],
+      "type": "object"
+    },
+    "url": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

First observedSep 25, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Annotations declare readOnlyHint=false, idempotentHint=false and openWorldHint=true; the description adds important behavioral context the annotations don't: rate limit (5 free per day per client address), inline-vs-link return threshold, and the full response fields (jobId, jobToken, links.file, sample, allowanceRemaining). This goes well beyond what annotations provide.

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?

Front-loaded with rate limit and core behavior, then conditional return behavior, usage routing, a concrete example, and response fields. Every sentence carries new information and the structure is logical.

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

Completeness5/5

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

Given 5 parameters, nested objects, 100% schema coverage, an output schema, and the presence of many siblings, the description is complete: it covers limits, return behavior, when to use vs. get_screenshot, and a concrete example. Nothing an agent needs is missing.

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% and descriptions are thorough, so baseline is 3. The description still adds value by showing the URL+viewportWidth example and naming the return values tied to jobToken, but it doesn't mention auth, visual.masks, visual.freeze, or idempotencyKey semantics beyond what is in the schema.

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?

States a specific verb+resource (capture screenshot as full-page PNG of one URL at a viewport width) and explicitly distinguishes from get_screenshot and comparison jobs. An agent can tell this apart from siblings without opening schemas.

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

Usage Guidelines5/5

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

Explicit when-to-use ('one-off look at a page or a mobile-width check') and when-not-to-use ('Do not call it for pages a comparison job covers: get_report names their screenshots for get_screenshot'), plus a concrete example call.

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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Give agents eyes on the webHosted screenshot MCP. Send a URL, get a pixel-perfect image. $0.002 per grab. Works with Claude, Cursor, and Codex.grabbit.liveAd

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