x402_qrcode

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It reveals that the tool incurs a cost of $0.01 USDC per call and returns a PNG image, which are useful behavioral traits. However, it doesn't mention side effects, error handling, rate limits, or authentication requirements. For a simple generator, this is adequate but not comprehensive.

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, concise sentence that front-loads the purpose (QR code generator) and includes the key behavioral note (returns PNG, cost). Every word earns its place, with no redundancy or fluff.

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 simple tool with two parameters and no output schema, the description covers the essential points: what it does, the output format, and the cost. It doesn't specify how the PNG is delivered (e.g., URL, base64) or any required headers, but given the tool's simplicity and lack of output schema, it is mostly complete. A mention of the response format would push it to a 5.

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%—both 'text' and 'size' are described in the schema. The description does not add additional parameter meaning beyond what the schema provides. The baseline for high schema coverage is 3, and the description doesn't elevate it by offering format details or edge-case guidance.

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 explicitly states the tool generates QR codes and returns a PNG image, with a clear verb and resource. This distinguishes it from sibling tools like x402_search or x402_image, which have different purposes. The cost note is additional context but doesn't obscure the core function.

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 description provides no guidance on when to use this tool versus alternatives. It doesn't mention scenarios where a different tool (e.g., x402_image for general image generation) might be preferred, nor does it state exclusions or prerequisites. The purpose is clear enough to infer usage, but explicit guidance is absent.

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