preview_qrcode

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

The readOnlyHint annotation already establishes that this is a safe read operation. The description adds useful behavioral context by stating that the tool returns a PNG image for inspection, which is valuable given there is no output schema. It does not overpromise or contradict the annotations.

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?

Two concise sentences, with the core purpose front-loaded and the sibling distinction stated immediately after. Every sentence carries useful information and there is no redundancy.

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?

For a preview tool with readOnlyHint true and a fully documented input schema, the description covers the essential context: what it produces, that it returns the image, and how it differs from the placement tool. No critical information appears to be missing for an agent to call it correctly.

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 input schema already documents all four parameters with 100% coverage, so the description is not required to explain them. The description adds general context about generating an invitation QR code but does not add parameter-level meaning beyond the schema. Baseline 3 is appropriate.

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 states a specific verb and resource: 'Generate a QR-code PNG for an invitation.' It also clarifies the return value ('Returns the image so it can be inspected'), distinguishing it from set_card_project_qrcode, which places the QR code on a card. This is a clear and differentiated purpose.

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 explicitly names the sibling alternative set_card_project_qrcode and contrasts previewing the image with actually placing it on a card. This gives an agent direct guidance for choosing between the two related tools.

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