pnetlab-mcp-server

list_images

Retrieve available disk images for a template, ensuring QEMU nodes start without crashing. See backend-specific image options for non-QEMU node types.

Instructions

List the disk images available for a template (e.g. mikrotik-7.23.2) plus the default image. Call this before add_node to get a valid image string for a QEMU node -- without one the node starts and immediately crashes.

For non-QEMU types (vpcs/iol/dynamips/docker) this lists whatever images that backend offers.

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": {
      "template": "<template>"
    },
    "name": "list_images"
  }
}

Input Schema

Name	Required	Description	Default
`template`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.1Jul 31, 2026

TDQS

A4.9/5.0

Behavior5/5

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

With no annotations, the description carries full responsibility. It discloses a critical behavioral detail: omitting a valid image causes immediate crash. It also transparently notes that behavior varies for non-QEMU types, which is valuable context beyond the schema.

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?

Three sentences, front-loaded with the primary purpose, followed by essential usage guidance and a clarification for other backends. Every sentence adds value and there is no fluff.

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?

For a low-complexity tool with one parameter and an output schema, the description fully covers the necessary context: what it lists, why you need it, and how behavior changes across backends. It is complete without needing to document return values.

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

Parameters4/5

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

Schema coverage is 0% and the only parameter 'template' is minimally described. The description compensates with a concrete example and clarifies that template refers to a template identifier. While not exhaustive, it gives sufficient semantic meaning for a single obvious parameter.

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 verb ('List') and resource ('disk images available for a template'), and provides a concrete example (mikrotik-7.23.2). It also distinguishes itself from sibling tools like list_templates by focusing on images and by linking to add_node usage.

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

Usage Guidelines5/5

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

Explicitly instructs to call this before add_node to get a valid image string, and explains the consequence of not doing so (node crashes). It also clarifies behavior for non-QEMU backends, giving clear context on when and why to use the tool.

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