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JorgeAlbareda

PrusaSlicer-MCP

cancel_print

Destructive

Stops the current print on a networked Prusa printer and requires explicit user confirmation before proceeding.

Instructions

Cancel the current print. Needs the user's explicit confirmation.

Input Schema

NameRequiredDescriptionDefault
hostYes
confirmation_codeNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

B3.2/5.0
Behavior3/5

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

destructiveHint=true already tells the agent this is a destructive operation, so the description is not carrying the full burden. It does add genuinely useful context beyond the annotation: an explicit user-confirmation requirement. But it omits key behavior for a destructive action — whether the job is recoverable, what happens to uploaded gcode, and how confirmation is actually obtained.

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 short sentences, zero filler, with the destructive action front-loaded ahead of the precondition. Nothing needs to be cut and the important constraint is not buried.

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 tool with no output schema, 0% parameter coverage, and an undocumented confirmation_code field, the description is too thin. It leaves unresolved whether confirmation is a UI dialog or the code parameter, and gives no post-cancellation state information an agent would need before invoking it.

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% and neither parameter is mentioned in the description. The required 'host' and the optional 'confirmation_code' are left entirely unexplained, and the description does not clarify how the 'explicit confirmation' it mentions relates to the confirmation_code parameter — a significant gap it should have filled.

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 specific verb (Cancel) and resource (the current print), making the operation immediately identifiable. It is distinguishable from siblings like pause_print/resume_print by the word 'cancel', but it never explicitly contrasts them (e.g., that cancel terminates rather than suspends the job), so it falls short of full sibling differentiation.

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

Usage Guidelines3/5

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

It gives one precondition — the user's explicit confirmation is required — which is real usage guidance. However, it does not say when to prefer cancel over pause_print/resume_print, nor what state the print must be in for cancellation to be valid, leaving usage largely implied.

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