gecko-mcp

Overview Schema Source Related Servers Discussions Admin

get_value

Read-only

Read the current value of any input, textarea, or select element using a CSS selector. Retrieves field content, including password fields, for the active browser tab.

Instructions

Read the current value of an input, textarea, or select by CSS selector. SENSITIVE: this CAN read the value of password fields and other secrets the user has typed — only use it on fields the user asked about, never to harvest credentials a page is requesting. Targets the active tab unless a browserId is 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>"
    },
    "name": "get_value"
  }
}

Input Schema

Name	Required	Description	Default
`selector`	Yes	CSS selector of the field to read.
`browserId`	No	Target tab (from list_tabs). Defaults to active.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.2.4Jun 20, 2026

TDQS

A4.5/5.0

Behavior5/5

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

Annotations indicate readOnlyHint and openWorldHint; description adds critical context about reading password fields and secrets, and default active tab behavior. No contradiction with annotations.

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 sentences, front-loaded key action, no redundant words.

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?

Covers tool scope, safety, and targeting. No output schema needed for simple read. Adequate for the task.

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% with clear descriptions. Description adds minimal extra meaning (defaults to active tab) beyond 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?

Description specifies verb 'read', resource 'current value of input/textarea/select', and method 'by CSS selector'. Clearly distinguishes from sibling tools like get_attribute or evaluate.

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?

Provides explicit sensitivity warning about credentials and guidance on when to use (only on user-asked fields). Does not explicitly contrast with alternatives like get_attribute.

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