vmware-mcp

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Write VM Variable

vm_write_variable

Write a value to a virtual machine’s configuration, guest environment, or runtime state, enabling you to update VM settings or environment variables directly.

Instructions

Write a variable to the VM state.

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": {
      "var_type": "<var_type>",
      "name": "<name>",
      "value": "<value>"
    },
    "name": "vm_write_variable"
  }
}

Input Schema

Name	Required	Description
`vm`	No	VM name or .vmx path
`name`	Yes	Variable name to write
`value`	Yes	Value to set
`var_type`	Yes	runtimeConfig: stored in .vmx file. guestVar: non-persistent runtime value. guestEnv: guest environment variable

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Aug 30, 2026

TDQS

C2.9/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only implies a mutating write operation and does not mention persistence semantics, side effects, required VM state, permissions, or failure behavior. The schema's var_type descriptions cover some details, but those are structured fields, not the tool description.

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?

The description is a single short sentence with no filler or redundant elaboration. It front-loads the verb and object, though it is so brief that it sacrifices useful detail.

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?

For a mutating tool with no annotations, no output schema, and an important var_type enum, the description is incomplete. It omits when the operation applies, what the different variable categories imply for behavior, and what the caller should expect after invocation.

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 description coverage is 100%, so the input schema already documents all parameters and the var_type enum meanings. The description adds no parameter-level explanation beyond what the schema provides, which matches the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a clear verb and resource: 'Write a variable' to 'the VM state.' This is specific enough to identify the operation, though it does not name the var_type distinctions or explicitly differentiate it from sibling tools such as vm_read_variable.

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

Usage Guidelines2/5

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

There is no guidance about when to use this tool versus alternatives, no prerequisites, and no exclusion criteria. The agent must infer usage entirely from the name and schema, since the description only says 'Write a variable to the VM state.'

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