Generate Styled QR Code

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

Annotations declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. The description adds the $0.05 cost disclosure, which is genuinely useful behavioral context beyond annotations. It does not contradict annotations. However, it doesn't disclose the payment-required behavior trait (that calls without _payment will fail on first attempt) in the main description, though this is partly covered in the parameter description. With annotations already covering safety, a 3 is fair.

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 a single efficient sentence that captures purpose and cost without waste. It's appropriately brief given the rich schema coverage. Not quite a 5 because it could use the front-loading opportunity to add one more differentiator (e.g., 'Use for branded/visually customized QR; use qr.generate for standard QR'), but it's lean and effective.

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?

The tool has 10 params, 100% schema coverage, an output schema, and strong annotations. The description covers the styling angle and cost. The payment workflow is the main gap - the agent needs to understand the two-step payment flow (call without _payment, get requirements, retry), which is only hinted in the parameter description, not the tool description. Still, the combination of schema + annotations + description is reasonably complete.

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 schema documents all 10 parameters with descriptions. The description adds the pricing detail and the payment flow hint but doesn't add meaning to individual parameters beyond schema descriptions. Baseline 3 for high coverage is appropriate - the description doesn't need to repeat parameter detail.

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 clearly states it generates an artistic/styled QR code with custom shapes, colors, and gradients - a specific verb+resource. It distinguishes from the sibling qr.generate by emphasizing styling/customization, though it could be more explicit about how it differs from the plain version.

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?

The cost mention ('Costs $0.05 USDC') and the _payment parameter guidance ('Get the requirements from a first call without _payment, then retry.') give useful contextual guidance. However, there's no explicit statement of when to use this vs qr.generate (plain QR) or when NOT to use it, leaving the agent to infer the differentiation from the word 'styled.'

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