gecko-mcp

by Frumane

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TypeScript

Local

set_checked

Set a checkbox or radio button to checked or unchecked state in a browser tab using a CSS selector.

Instructions

Check or uncheck a checkbox/radio. Active tab unless browserId given.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "selector": "<selector>",
      "checked": "<checked>"
    },
    "name": "set_checked"
  }
}

Input Schema

Name	Required	Description
`selector`	Yes	CSS selector of the checkbox/radio.
`checked`	Yes	true to check, false to uncheck.
`browserId`	No	Target tab. Defaults to active.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.2.4Jun 20, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations declare readOnlyHint=false (write operation) and destructiveHint=false (safe). Description adds behavioral context about tab targeting. No contradiction; description supplements annotations by clarifying scope.

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?

Two short sentences convey purpose and scope without fluff. Front-loaded with the primary action. Every sentence earns its place.

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 simple setter tool with 3 parameters, the description is sufficient. Notes default active tab. No output schema, so return details not needed. Minor omission: prerequisites like element visibility, but not critical for basic use.

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 covers 100% of parameters with clear descriptions. Description adds no new meaning beyond summarizing the operation. Baseline 3 for high schema coverage.

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?

Description clearly states the tool checks or unchecks a checkbox/radio, specifying the resource and action. It distinguishes from siblings like 'click' by directly targeting checkbox state.

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?

Description indicates default active tab and optional browserId, providing context for when to use the browserId parameter. It implicitly suggests use for setting checkbox state but does not explicitly compare to alternatives like 'click'.

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