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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds meaningful context beyond annotations: auth mode ('user-auth mode, active session'), the dependency on `ethora-app-select`, and specific error codes (400 no app selected, 401 not logged in). This is useful operational detail not present in the annotations. No contradictions found.

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 description is efficient: a first sentence states the core action and outcome, a second sentence covers auth and errors, and the final line names the related tool. Every sentence earns its place, and the key purpose is front-loaded. No fluff or redundancy.

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?

For a simple read-only tool with no parameters and no output schema, the description covers all essentials: what it returns (rooms with JIDs and titles), the auth requirement, the dependency on a previously selected app, error conditions, and the alternative for explicit appId. An agent has everything needed to invoke it correctly.

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 input schema is empty (0 parameters), so there is nothing to document. The description correctly does not invent parameters. Baseline for 0 params is 4, and the description does not need to add anything about parameters. It effectively communicates that no parameters are needed.

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 ('List') and a specific resource ('default chat rooms (MUC rooms) of the currently selected Ethora app'), and clarifies the auto-join behavior. It also distinguishes itself from the sibling by naming the alternative that takes an explicit appId. This is a clear, unambiguous purpose.

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 description explicitly references the sibling tool `ethora-app-get-default-rooms-with-app-id` and explains when to use it (to pass `appId` explicitly). It also states the prerequisite that an app must be selected via `ethora-app-select`. This gives clear when-to-use and when-not-to-use guidance, with an alternative named.

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