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fileforge_responsive_action

Scan a URL across viewport widths to detect layout bugs such as horizontal overflow and overlapping elements, and capture screenshots at a width matrix for comparison.

Instructions

Find layout bugs across screen widths: scan a URL, and locate overflow and overlapping elements. capture_matrix takes a screenshot at each viewport. Use fileforge_visual_action to compare screenshots against baselines. Loads the page in your session and can store results; it doesn't change the site. Needs the extension.

Input Schema

Name	Required	Description	Default
`url`	No	Page URL to scan. Required for scan_layout and capture_matrix.
`store`	No	Save the result in ~/.fileforge and return a ref.
`tabId`	No	Tab ID, or "active" for the active tab.	active
`action`	Yes	What to do. Required parameters are in brackets. scan_layout (url): Scan layout for responsive issues across widths. find_overflow: Find horizontal overflow at responsive widths. find_overlaps: Find overlapping element boxes. capture_matrix (url): Capture screenshots at a width matrix.
`checks`	No	Checks to run. Defaults apply if omitted.
`widths`	No	Viewport widths to test

Output Schema

Name	Required	Description
`ok`	Yes	False if the action failed or a check did not pass.
`ref`	No	Stored result ID, for fileforge_result_action.
`data`	No	The result. Its shape depends on the action.
`meta`	No	Tool, action and context.
`error`	No	Failure code and message.
`warnings`	No	Notes about a call that still ran.

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedv0.3.0Nov 5, 2026

changedInput schema / properties / action / description

Previous value: -"The responsive action to perform."New value: +"What to do. Required parameters are in brackets. scan_layout (url): Scan layout for responsive issues across widths. find_overflow: Find horizontal overflow at responsive widths. find_overlaps: Find overlapping element boxes. capture_matrix (url): Capture screenshots at a width matrix."

addedInput schema / properties / checks / description

Added value: +"Checks to run. Defaults apply if omitted."

addedInput schema / properties / store / description

Added value: +"Save the result in ~/.fileforge and return a ref."

addedInput schema / properties / tabId / description

Added value: +"Tab ID, or \"active\" for the active tab."

addedInput schema / properties / url / description

Added value: +"Page URL to scan. Required for scan_layout and capture_matrix."

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "description": "query_* actions return their modules as extra top-level fields.",
+  "properties": {
+    "data": {
+      "description": "The result. Its shape depends on the action."
+    },
+    "error": {
+      "description": "Failure code and message."
+    },
+    "meta": {
+      "description": "Tool, action and context."
+    },
+    "ok": {
+      "description": "False if the action failed or a check did not pass.",
+      "type": "boolean"
+    },
+    "ref": {
+      "description": "Stored result ID, for fileforge_result_action."
+    },
+    "warnings": {
+      "description": "Notes about a call that still ran."
+    }
+  },
+  "required": [
+    "ok"
+  ],
+  "type": "object"
+}

First observedv0.2.1Nov 5, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Adds real context beyond the annotations: 'Loads the page in your session and can store results; it doesn't change the site' explains why readOnlyHint is false even though the site itself is untouched, and 'Needs the extension' discloses a prerequisite the annotations do not carry. It stops short of describing the matrix defaults or what 'store' produces at runtime.

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 sentence and the remaining sentences each carry distinct information (screenshot behavior, alternative tool, side effects, prerequisite). A couple of fragments ('capture_matrix takes a screenshot at each viewport.') read as tacked on rather than integrated, which keeps it from a 5.

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?

For a six-parameter, four-action tool with an output schema and full annotation coverage, the description covers purpose, the closest alternative, side effects, and the extension dependency. Return values need not be explained given the output schema, so nothing critical is missing.

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 coverage is 100%, so the enum descriptions already explain each action and its required parameters. The prose only restates that 'capture_matrix takes a screenshot at each viewport' and adds nothing about widths, checks, or store semantics beyond the schema, so the baseline 3 applies.

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 and resource: 'Find layout bugs across screen widths: scan a URL, and locate overflow and overlapping elements.' It also names the sibling it is not ('Use fileforge_visual_action to compare screenshots against baselines'), so an agent can distinguish this from the visual-regression tool without opening either schema.

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?

Gives clear routing guidance: this tool scans/captures, while fileforge_visual_action handles baseline comparison. The action enum covers the individual scan variants, but the prose does not state when to prefer find_overflow versus scan_layout, leaving that to the schema.

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