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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered structurally. The description adds only the returned-signal list and the 'No image' confirmation, without disclosing validation behavior details (e.g. whether capacity % fails hard or warns).

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 compact sentence that front-loads the return payload and ends with the key exclusion ('No image'). No filler.

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?

With no output schema, zero schema coverage on four params, and a nested payload object, the description leaves the agent guessing at input semantics and return shape. The output-list sentence helps but does not compensate for the undocumented nested object.

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 0% for four parameters, including a nested `payload` object, an `ecc` enum, and a `margin` integer. The description alludes only loosely to 'ECC' and 'quiet-zone' without mapping them to parameter names, and does not explain the relationship between `data` and `payload` or acceptable `margin` units.

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 (Return) and enumerates exactly what is returned: version, ECC, module count, capacity %, and quiet-zone/density warnings. The 'No image' clause distinguishes it from the sibling qr_generate, though that differentiation is implicit rather than by name.

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 no when-to-use guidance, no exclusions, and does not name any alternative. 'No image' hints at the boundary with qr_generate but never states 'use qr_generate for an image, use this to validate capacity.' The agent must infer the workflow context.

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