Check App Links / Universal Links files

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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description adds real value beyond that by stating the output shape (severity ok/warn/error plus a fix) and that no API key is needed. It doesn't mention rate limits or failure behavior for unreachable domains, which keeps it from a 5.

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?

Front-loaded with the concrete files checked, then trigger, then scope caveat, then auth note. Dense and nearly waste-free; the parenthetical platform annotations are slightly verbose but useful.

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?

No output schema exists, yet the description tells the agent what findings look like (severity levels and a fix) and sets expectations about what is out of scope (actual device behavior). Nothing needed to call it correctly is missing.

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?

Only one parameter and schema coverage is 100%, with the schema already explaining that a full URL is reduced to its host. The description adds no format or edge-case guidance about the domain beyond what the schema states, so 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?

Names the exact resources checked (assetlinks.json, apple-app-site-association) and the platforms, so the agent knows this is a domain-level file validator rather than a link tester. It is clearly distinct from siblings like check_link or simulate_tap.

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?

Gives an explicit trigger condition ('when links open the browser instead of the app') and an explicit scope exclusion ('checks the files the domain serves, not how one particular phone behaves'). It does not name the neighboring tools an agent might confuse it with, such as check_link or simulate_tap, so it stops short of full alternative routing.

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