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

With no annotations provided, the description carries the behavioral disclosure burden. It does well by revealing that saved artwork is returned when present, otherwise a plain code is rendered, and by disclosing the API key and plan requirement. It does not describe the exact return transport, but the behavior is substantially transparent for a read-only fetch operation.

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 three sentences with no filler. It front-loads the core purpose, explains the conditional behavior in the second sentence, and closes with the access requirement. Every sentence earns its place.

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 definition covers the main behavioral variants, auth requirements, and the meaning of 'plain' versus saved artwork. Since there is no output schema, it would be slightly stronger if it stated the exact return format, but the wording 'QR code ... ready to print' and the format parameter sufficiently imply the result for typical 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?

Schema description coverage is 100%, so the schema already documents every parameter clearly. The description adds useful context about stored artwork, frames, colours, and logos, but it does not need to add parameter-level meaning and does not go significantly beyond the schema.

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 opens with a specific verb and resource, 'Fetch the QR code for an existing link', and clearly distinguishes itself from sibling tools like create_qr by emphasizing 'existing link'. It also explains the two possible result modes, stored artwork or plain code, which removes ambiguity about what the tool returns.

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 implies usage context: use it when you have an existing link and need a print-ready QR code, and it warns about the Business plan requirement. However, it does not explicitly name alternatives such as create_qr or state when this tool should not be used, leaving the routing decision mostly to inference.

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