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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds no behavioral context of its own — nothing about what the QR code object contains or whether image data is included (that lives in get_qr_code_image).

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?

A single front-loaded sentence with no waste; the identifier is mentioned immediately. It is arguably too terse rather than padded, which is a minor defect.

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 one-parameter read tool with full annotation and schema coverage and no output schema, this is nearly sufficient. The only missing nuance is that the returned record is metadata rather than an image, which would have routed the agent to get_qr_code_image.

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 coverage is 100% and the qrId property already documents its provenance ('from list_qr_codes or create_qr_code'). The description merely restates 'by qrId', adding no semantics beyond the schema, so baseline 3 applies.

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?

States a specific verb (fetch) and resource (one QR code) with the identifying key qrId. The word 'one' implicitly contrasts with list_qr_codes, but no sibling is named explicitly, so differentiation is only partial.

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?

Usage is only implied: an agent can infer this is the single-record retrieval counterpart to list_qr_codes. There is no explicit statement of when to use this versus get_qr_code_image, get_qr_code_stats, or list_qr_codes.

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