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

The description discloses the key behavioral trait that providing qr_id updates the existing link while preserving the short link and QR code, and it states the input requirement of app_name plus at least one store URL. It does not cover failure modes, permissions, or side effects, but it adds meaningful behavior beyond the sparse annotations.

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, each earning its place: purpose, use cases, then requirements and update semantics. The device-routing concept is front-loaded in the first clause, and there is no filler or repetition of schema details.

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?

Given the output schema exists and annotations are minimal, the description provides all operational knowledge an agent needs: required app_name, the one-of-two URLs constraint, optional icon URL, and the qr_id update behavior. Nothing essential for calling the tool correctly is left to inference.

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 baseline is 3, but the description adds a critical business rule not visible in the schema: although ios_url and android_url are individually optional, at least one must be provided. It also clarifies that qr_id switches the tool into update mode, which is not inferable from the parameter description alone.

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 and resource: create (or update) a device-routing smart link and dynamic QR code. It distinguishes itself from sibling short-link tools by explicitly mentioning iPhone-to-App-Store and Android-to-Google-Play routing, which makes the tool's purpose unmistakable.

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 clear use cases ('download our app' campaigns in print, ads, websites, link-in-bio pages), which tells an agent when to select this tool. However, it does not explicitly contrast with siblings like save_short_link for generic links, nor does it state when not to use this tool.

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