MCP 3D Printer Server

cancel_print

Stop an active 3D print job on your printer. This tool cancels the current print via the MCP 3D Printer Server.

Instructions

Cancel the current print job

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "cancel_print"
  }
}

Input Schema

Name	Required	Description
`host`	No	Hostname or IP address of the printer (default: value from env)
`port`	No	Port of the printer API (default: value from env)
`type`	No	Type of printer management system (octoprint, klipper, duet, repetier, bambu, prusa, creality) (default: value from env)
`api_key`	No	API key for authentication (default: value from env)
`bambu_token`	No	Access token for Bambu Lab printers (default: value from env)
`bambu_serial`	No	Serial number for Bambu Lab printers (default: value from env)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.9Sep 29, 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 disclosure burden. It does not state that cancellation is destructive and non-resumable, whether it aborts an in-progress print or just clears the queue, or what authentication/permissions are required.

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?

A single front-loaded sentence with zero filler. It is efficient, though its brevity is partly under-specification rather than disciplined economy.

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 destructive mutation tool with no annotations, no output schema, and six connection parameters silently defaulting from environment variables, the description is too thin. It should at minimum say the cancel is irreversible and note that host/type/api_key default from env.

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% and all six parameters are optional with env fallbacks, so the schema already documents everything. The description adds no parameter-level meaning beyond that, which warrants the baseline 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?

States a specific verb (Cancel) and resource (the current print job), which is enough to distinguish it from siblings like start_print or process_and_print_stl. It does not explicitly call out cross-printer scope, but the core action is unambiguous.

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?

No when-to-use guidance, no prerequisites, and no reference to alternatives such as get_printer_status to confirm an active job before cancelling. The agent must infer all of this from the tool name alone.

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