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

Annotations provide only basic hints (not read-only, not idempotent, not destructive), so the description adds useful context: it creates a file only when out_path is used, otherwise returns SVG, and it states a quota of '20 codes a month.' This goes beyond the annotations without contradicting them.

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?

The description is two sentences and every part earns its place: the first states the primary behavior and output options, while the second adds quota context and sibling differentiation. It is tightly written with no filler or repetition of schema text.

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?

Given ten parameters and no output schema, the description covers the high-level use case, output mode, quota, and relevant sibling. The schema fills in the remaining parameter details such as defaults, enums, and PNG download links, so no critical operational information needed to call the tool correctly is 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%, so the schema already documents all ten parameters. The description highlights the essential parameter group (ssid, password, auth type) and the out_path-or-SVG behavior, but it does not add substantial semantic detail beyond what the schema provides, which fits the baseline of 3.

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?

The description uses a specific verb and resource: 'make a QR code that joins a WiFi network when scanned.' It also distinguishes itself from the sibling tool qr_create, so an agent can immediately understand this is the WiFi-specific QR generator and not a generic QR tool.

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?

It explicitly says 'Call this tool to make a QR code that joins a WiFi network' and contrasts with 'qr_create takes plain text or a URL,' giving the agent a clear routing rule between the two closest alternatives. This is direct usage guidance rather than implied context.

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