QR code

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false), the description adds real behavioral context: files get written to disk, PNG output is gated behind Pro, and the free tier is rate limited to 20 codes/month. The write side-effect path is partially covered by the schema's overwrite flag, so the description is additive but not exhaustive about overwrite semantics.

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 verb and resource, then the output modes, then the return shape and quota. No filler; every clause carries actionable information.

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 7-parameter tool with one required field and no output schema, the description covers the output modes, the file-writing requirement, the Pro gate, and even the return shape (version, module grid, payload size). Only the alternative-sibling routing and overwrite consequences are left implicit.

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 every parameter including default margin, error_correction levels, and size range is already documented. The description reinforces the format/size/out_path relationship and the Pro constraint on PNG, but adds no syntax or default information the schema lacks — baseline 3 applies.

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 concrete verb and resource ('turn text or a URL into a QR code') and names the two output modes (inline SVG, PNG to out_path), so the operation is unambiguous. It stops short of differentiating itself from the specialized siblings qr_wifi, qr_vcard, and qr_payment_sepa, which an agent would still have to infer is the generic-vs-preset split.

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?

'Call this tool to turn text or a URL into a QR code' gives an implied use condition plus a tier prerequisite (PNG requires Pro) and a quota (20 free codes/month). There is no explicit guidance on when to prefer this over the preset siblings or barcode_create, and no when-not-to-use statement.

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