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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so "Read-only" adds no new information. The value-add is the enumeration of returned fields, which matters because there is no output schema; it does not mention error behavior for a nonexistent ID or whether deleted codes are retrievable.

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 sentences, front-loaded with the use condition, then the returned payload, then the prerequisite fallback. No filler or restatement of the title.

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 no output schema, the description covers the trigger condition, the alternative when the ID is unknown, the safety profile, and the contents of the response. An agent has everything needed to call it correctly.

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?

Single parameter `idqrcode` is fully documented in the schema (100% coverage), so the schema carries the semantics. The description only reinforces that lookup is by ID and adds no format, source, or validity guidance beyond that — 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 and resource (fetch one QR code by ID) and enumerates the payload the caller gets back: type, name, destination, short link, styling, preview image, download link. This clearly separates it from `list_qrcodes` and from the many other `get_*` siblings (scans, history, wallet link, variant rules).

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 scopes usage to the case where the user names one specific QR code by ID, and names the fallback: "If you don't have the ID, call `list_qrcodes` first." Both the when and the alternative are stated rather than inferred.

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