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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description needn't repeat that. It adds context: 'Rendered on our server' and 'Price: free', which are behavioral details not present in the schema. It doesn't disclose error handling or rate limits, but given the strong annotation coverage, this is a minor gap.

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 core purpose, and packed with necessary details (formats, options, special cases, pricing). No filler or redundancy.

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 9-parameter tool with no output schema, the description covers the essential usage: it explains the primary inputs, special parameter combinations, and output format. It doesn't detail edge cases or error behavior, but for a simple generator tool this is adequate. The description is nearly complete for an agent 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?

Schema description coverage is 0%, so the description must compensate, and it does. It explains the meaning of text for Solana Pay, and the wifi_ssid/wifi_password pair for Wi-Fi. It also mentions size, margin, colours, and error correction, mapping to the schema parameters. This adds significant value beyond the bare parameter names.

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 states a specific verb ('Make') and a specific resource ('QR code'), and enumerates supported content types (text, URL, Solana Pay/wallet address, Wi-Fi login) and output formats (PNG/SVG). It clearly distinguishes this tool from any sibling by focusing on QR generation, which none of the listed siblings handle.

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 gives explicit instructions for special cases: 'For Wi-Fi pass wifi_ssid + wifi_password; for Solana Pay pass a solana: URI as text.' This tells an agent exactly how to configure parameters for different use cases. It doesn't mention alternatives because there are no QR-specific siblings, but the guidance is sufficient for correct invocation.

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