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

Beyond the readOnlyHint and destructiveHint annotations, the description discloses meaningful behavior: the PNG is inline and frameless, download links are signed and valid for 24 hours with no sign-in, and the SVG is the print-ready version with frame, colors, and logo. This adds substantial context about what the tool returns and how the links behave.

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 front-loaded with the primary purpose and then efficiently explains return formats, link behavior, and the size parameter. Every sentence adds useful information without redundancy, and the length is appropriate for the tool's complexity.

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?

The description covers the key workflow context ('Call this after create_qr_code'), return formats, and link expiry. An output schema exists, so return-value details need not be repeated. The only minor gap is not explicitly naming the id parameter, but the sequencing hint makes it inferable.

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?

With 0% schema description coverage, the description must compensate. It explains 'size is the PNG width in px (256-2048),' which adds semantic meaning beyond the schema's min/max/default. However, the required 'id' parameter is only implicitly referenced via 'Call this after create_qr_code,' leaving its role under-specified.

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: 'Show the user their QR code, or hand them a file to save.' It clearly identifies the tool as returning the QR image, distinguishing it from sibling tools like get_qr_code by focusing on image retrieval and download links.

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 gives explicit usage context: 'Call this after create_qr_code.' It also describes two use cases—displaying inline or saving via download links—which helps an agent decide when to invoke it. It does not explicitly contrast with get_qr_code, but the sequencing and output details provide sufficient guidance.

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