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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so 'Changes nothing' largely restates structured data. What the description does add is genuinely needed since there is no output schema: it names the returned fields (ids and domains), telling the agent what shape the response takes and that the ids feed downstream umami_ calls.

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 short sentences, front-loaded with what the tool returns, then ordering guidance, then the safety note. No filler and no restating of the title.

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?

With no parameters and no output schema, the description carries the output burden and does so by naming the returned fields, plus it tells the agent to call this before other umami_ tools. Nothing an agent needs in order to invoke 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?

The tool takes zero parameters, so there is nothing to disambiguate and the baseline of 4 applies. The description correctly implies a full, unfiltered listing with no arguments to supply.

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?

Identifies the specific resource (the websites in the user's Umami analytics) and even the return payload (ids and domains), which cleanly separates it from ga4_properties, gsc_properties and other property-listing siblings. The verb is only implicit ('The websites in...') rather than stated as 'list', which keeps it just short of a 5.

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?

'Start here before the other umami_ tools' gives explicit sequencing guidance that an agent can act on, and the '(self-hosted or Umami Cloud)' parenthetical clarifies which deployments it covers. There is no when-not-to-use clause or statement about what happens if no websites exist, so it stops at clear context rather than full routing.

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