List users

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

Annotations already declare it read-only, idempotent, non-destructive and closed-world, so safety is fully covered. The description adds that ids are returned (useful for chaining, since there is no output schema), but says nothing about ordering, paging, or whether disabled/shared accounts are included.

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?

Two short sentences, front-loaded with what the tool returns and followed by the practical follow-up action. 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?

With no input schema to explain, annotations covering the safety profile, and no output schema, the description carries the burden for return shape and does note it returns accounts with ids. Minor gaps (ordering, scope of accounts) keep it from full marks.

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 the baseline is 4; nothing about parameter semantics needs to be stated or could be added.

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?

"All Plex accounts on this server with ids" states a specific resource and its key output field, which is enough to distinguish it from the many listing siblings (list_libraries, list_media). It does not explicitly contrast with those siblings, but the resource is unambiguous.

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?

The second sentence gives a concrete downstream use: feed names or ids into watch_history's user filter. That is clear chaining guidance, though it never states when not to use this tool or what to do if only names are needed.

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