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

Annotations already cover the safe, read-only, idempotent, closed-world profile, so the description's added value is stating that it validates and returns a string rather than an image — genuinely useful given there is no output schema. It stops short of saying what happens on an invalid payload (error vs. partial string).

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?

Two tight sentences with the verb and type list front-loaded and the return-shape caveat at the end; every clause carries information. No filler or restatement of the tool name.

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 tool taking a nested, schema-undocumented object across eight payload types, the description supplies only one worked example, so an agent cannot reliably construct vcard, geo, mailto, tel or sms payloads. Validation semantics (what constitutes invalid, what error looks like) are also unstated, leaving substantial gaps for this level of schema complexity.

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 0% and the single parameter is a free-form nested object whose schema only pins the 'type' enum, leaving per-type keys undefined. The wifi example (ssid, password) adds real meaning the schema lacks, but it documents only one of eight types, so mailto/vcard/geo/sms required fields remain guesswork.

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 pair (build and validate) and resource (QR payload string), and enumerates the supported payload types, which is more than the title alone conveys. It implicitly separates itself from qr_generate with 'Returns the string only', but never names a sibling outright.

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 must infer that this is the step before qr_generate/qr_inspect and that it is the right tool when you want a payload string rather than an image. There is no explicit when-to-use, when-not-to-use, or named alternative.

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