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

With no annotations, the description carries the full burden and does reasonably well: it discloses the auth model (free, no key), output form (SVG URL, ready to download), and persistence ('never expires'). It omits failure modes and rate limits, but the key behavioral facts an agent needs are present.

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 short sentences, front-loaded with the verb and output, then auth, then input breadth. Efficient, though the inline WiFi example string is slightly heavy and could have been trimmed.

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 5-param tool with no annotations and no output schema, the description covers purpose, auth, output type, lifetime, and input formats. Error behavior is unaddressed but is a minor gap given the schema fully documents the parameters.

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 100%, so the baseline is 3, but the description adds real value by showing the encoding syntax for structured payloads (e.g. 'WIFI:T:WPA;S:MyNet;P:secret;;', vCard, geo URI) that the schema's generic 'Text/URL to encode' does not convey.

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+resource ('Generate a static QR code') and even names the deliverable ('ready-to-download SVG URL'). The scope ('static... never expires') is unambiguous, so an agent knows exactly what it gets back without opening the schema.

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?

Gives clear operating context — 'Free, no key required' — and enumerates accepted input kinds (text, URL, WiFi credentials, vCard, geo URI), which tells the agent when this tool applies. No sibling tools exist, so there are no alternatives to route against, but it stops short of stating any exclusions or limits.

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