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

Annotations only provide false hints for readOnly, openWorld, idempotent, and destructive, so they do not describe side effects. The description adds meaningful behavioral context: the five-room quota for free accounts and the conditional promotion of the new room to delivery-room status, which affects where handoffs and direct questions land. This goes beyond what annotations convey.

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 uses three sentences, each adding distinct information: the core purpose, the quota limitation, and the delivery-room side effect. It is front-loaded with the main action and contains no redundant or filler phrasing.

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?

The description covers purpose, ownership, quota, and the side-effect condition, and an output schema is present, so return-value details are not needed. The only minor omission is an explicit pointer to create_public_room, but the word 'private' already signals that boundary, making the description complete enough for correct tool selection and invocation.

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 description coverage is 100%, so the input schema already documents name, icon, and color with examples and constraints. The description adds no parameter-level detail beyond what the schema provides, so the baseline score of 3 is appropriate.

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 opens with a specific verb and resource: 'Create a new private room owned by the authenticated account.' The 'private' qualifier clearly differentiates it from the sibling create_public_room, so an agent can correctly identify which tool to use.

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 provides clear context: this is for private rooms owned by the caller, and it explains the delivery-room condition when the agent has every room. It does not explicitly name create_public_room as the alternative for public rooms, but the private/public contrast and the sibling list make the intended use reasonably clear.

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