Create area

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

Annotations already declare idempotentHint=false and destructiveHint=false, but the description adds the concrete consequence: Home Assistant assigns the area_id, you cannot request one, and calling twice with the same name yields two distinct areas. It also discloses the return payload shape, which is genuine context beyond the hints.

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 action, then compact labeled sections (Use when / Not for / Returns) on separate lines. Every sentence carries information; there is no filler or repetition 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?

For a one-parameter create tool with annotations and an output schema, the description covers the operation, the non-idempotent pitfall, usage boundaries, and the return contents. An agent has everything needed to call 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?

Schema coverage is 100% and the single 'name' parameter is fully described in the schema, so the baseline is 3. The description adds a little beyond the schema by clarifying that name is the only input and that area_id cannot be specified, which is meaningful for a create operation.

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?

States a specific verb and resource ('Create a new Home Assistant area (room)') and names the underlying WS command. It also distinguishes itself from the sibling update concept by noting no update tool exists in this namespace, so the agent can place it precisely among the areas_* tools.

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?

Explicit 'Use when' (need a new area to assign devices, entities or labels to) and 'Not for' (renaming or moving an existing area, with the note that no update tool exists). Both the trigger and the exclusion are stated, leaving nothing to inference.

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