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

Annotations already flag destructiveHint=true and non-idempotency, so the bar is lower. The description still adds real behavioral context beyond the annotations: every link ships with a scannable QR code, clicks and scans are tracked in one dashboard, and supplying qr_id mutates the destination while preserving the existing short URL and printed QR code.

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 sentences, front-loaded with the creation purpose and followed by the qr_id update case and the sibling disambiguation. Dense but each sentence carries distinct information; no filler.

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?

An output schema exists, so return values need not be described. With creation, update-by-qr_id, tracking side effects, and sibling routing all covered, an agent has everything needed to select and call this tool 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 coverage is 100%, so baseline is 3. The description adds meaning on top of the schema by explaining the operational effect of qr_id (change destination while preserving the short URL and printed QR) and illustrating the custom slug format with a concrete branded example (qrkit.co/summer-sale).

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 names a specific verb+resource (create a branded short link and dynamic QR code for an existing URL) and explicitly covers the update variant via qr_id. It cleanly distinguishes itself from siblings like save_email_link and set_link_slug.

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?

It gives an explicit when-to-use trigger ('when the user already has a destination URL and wants to shorten or brand it, track visits, or get a QR code') and names the alternative sibling set_link_slug with the exact condition that selects it (renaming an existing slug).

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