Chrome Course MCP

by CrispyW0nton

Overview Schema Source Related Servers Discussions Admin

JavaScript

Local

chrome_select

Select a dropdown option on a web page using CSS selector or label text, matching by value or visible text.

Instructions

Set a select dropdown by CSS selector or label text, matching option value or visible text.

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": {
      "value": "<value>"
    },
    "name": "chrome_select"
  }
}

Input Schema

Name	Required	Default
`label`	No
`tabId`	No
`value`	Yes
`waitMs`	No
`debugUrl`	No	http://127.0.0.1:9222
`selector`	No
`urlContains`	No
`titleContains`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Jul 12, 2026

TDQS

A3.5/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It discloses the matching strategy but omits behavioral traits such as whether the page must be loaded, what happens if the element is not found, side effects, or return values. This is similar to the 'update_drive' example, which scored 2 for lacking such detail.

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?

The description is a single sentence that front-loads the verb and resource, with no unnecessary words. It is concise and easy to parse, matching the standard of the high-scoring example.

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

Completeness2/5

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

The tool has 8 parameters, no output schema, and no annotations, yet the description only covers the core action and two targeting modes. It does not explain how to scope the operation to a specific tab or page, or what the wait parameter does. This leaves significant gaps for an agent to select and invoke the tool correctly.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate. It adds meaning to selector and label (the two targeting mechanisms) and hints at value semantics ('option value or visible text'), but it leaves tabId, waitMs, debugUrl, urlContains, and titleContains entirely unexplained. This is insufficient for a tool with 8 parameters.

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?

The description clearly states the action ('Set a select dropdown'), the method ('by CSS selector or label text'), and the matching criterion ('matching option value or visible text'). It distinguishes this tool from siblings like chrome_click and chrome_type by specifying a select-specific operation.

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?

The description clearly implies the usage context: when you need to programmatically select an option in a dropdown. It doesn't explicitly mention alternatives or exclusions, but the context is clear enough relative to sibling tools that it earns a 4 rather than a 3.

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