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

Annotations already declare readOnly, idempotent, non-destructive and closed-world. The description adds genuinely new behavioral facts: the payload is baked into the pattern permanently, the result cannot be edited or tracked after printing, and there is a 1000-byte payload ceiling not present in the schema.

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?

Three sentences, front-loaded with the capability and constraint before the alternative. Efficient overall, though the closing trial/credit-card marketing clause is the least load-bearing part for an agent deciding how to call the tool.

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 readOnly/idempotent annotations and no output schema, the remaining burden is behavioral and payload-shape context, both of which are covered (permanence, byte cap, payload types). Nothing needed to invoke it correctly appears to be missing.

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% (baseline 3), so color, ECC, size and format semantics are already handled. The description adds value by enumerating the concrete payload forms accepted by `data` (text, URL, WIFI:..., vCard) and the 1000-byte limit that the schema's minLength does not express.

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 (create) and resource (static QR code image) plus output formats (PNG/SVG), the accepted payload types (text, URL, WiFi, vCard), and the 1000-byte cap. There are no siblings to distinguish from, but the scope is unambiguous.

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?

Explicitly frames when this tool fits (payload encoded directly, works forever) and when it does not (no editing, no scan tracking), then names the alternative path (dynamic QR code from qrcode.io). The alternative is an external product rather than a sibling tool, which slightly weakens the routing value.

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