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

Annotations already declare readOnly/idempotent/non-destructive, and the description reinforces this with 'without this server writing anything.' It goes beyond the annotations by disclosing the webhook signing scheme (Standard Webhooks, signed), the payload contract, supported channel types, the per-resort public Atom feed, and the human-facing manage page. That is substantive behavioral context a caller could not infer from the safety hints alone.

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?

The single long sentence is a comma-heavy enumeration of channels, contracts, and pages that mixes purpose with a parts list. It is front-loaded toward what the tool covers, but the run-on structure makes it harder to parse than it needs to be. Some listed items (iCal, Atom, manage page) could be trimmed or reorganized.

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 a single optional parameter, rich annotations, and an output schema (so return values need not be described), the description covers enough for correct invocation: what is returned, what the slug does, and that nothing is written. Only explicit sibling routing and any error/none-found behavior are 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?

Schema coverage is 100%, so the schema already documents the single optional slug parameter, including that it fills in the public Atom feed URL. The description restates this same effect ('Pass a slug to get that resort's feed URL') without adding format, constraints, or fallback behavior. Baseline 3 is appropriate when the schema carries the parameter burden.

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 clearly frames the resource: the alert threshold/schedule, delivery channels (e-mail, webhook, Atom, iCal), webhook payload contract, and the manage page. The verb is implied rather than stated ('How to be told when it snows'), but an agent can tell this returns alert-configuration information. It is distinguishable from siblings like get_forecast or find_powder, though it never names them.

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?

Usage is only implied: 'Pass a slug to get that resort's feed URL' tells the agent what the optional parameter accomplishes, and 'without this server writing anything' hints at a non-mutating context. There is no explicit when-to-use-this-vs-alternatives guidance, so the agent must infer that this is the documentation/reference tool rather than a data-lookup tool.

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