MCP Label Printer

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the action ('Print') and output format (label with QR code and text), but fails to disclose critical traits such as whether this requires printer connectivity, specific permissions, error handling, or side effects like paper consumption. For a hardware-interaction tool, this is a significant gap in transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, well-structured sentence that efficiently conveys the tool's purpose and key details without unnecessary words. It is front-loaded with the main action and resource, making it easy to parse quickly. Every part of the sentence contributes directly to understanding the tool's function.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity (hardware interaction with 4 parameters) and no annotations or output schema, the description is adequate but incomplete. It covers the basic purpose and parameter mapping but lacks behavioral context, error handling, or output details. For a tool that interacts with physical devices, more information would be beneficial to ensure reliable use.

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

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

The description adds minimal meaning beyond the input schema, which has 100% coverage with clear descriptions for all parameters. It mentions that the QR code links to the URL and text shows issue details, loosely mapping to the parameters but not providing additional syntax or usage details. Given the high schema coverage, the baseline score of 3 is appropriate as the schema does the heavy lifting.

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

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

The description clearly states the action ('Print a label'), the target resource ('to Brother QL-810W printer'), and the content ('with QR code and text'). It specifies that the QR code links to a URL and text shows issue details, making the purpose specific and actionable. However, with no sibling tools mentioned, it cannot demonstrate differentiation from alternatives, preventing a perfect score.

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

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

The description provides no guidance on when to use this tool versus alternatives, prerequisites, or exclusions. It implies usage for printing labels with issue details and QR codes but lacks explicit context or recommendations for specific scenarios. This minimal guidance limits its effectiveness for an AI agent in decision-making.

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