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

Annotations already indicate this is a write operation (readOnlyHint=false) and not destructive. The description adds behavioral context about slug generation for private rooms and slug choice for public rooms, which is useful. However, it doesn't disclose what happens on creation (e.g., whether the creator automatically joins, or what the response contains), though no output schema exists to cover that.

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 sentences, no wasted words. The core action is front-loaded, and the public/private distinction is stated efficiently. Every sentence earns its place.

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 creation tool with full schema coverage and clear annotations, the description is nearly complete. It could mention what happens after creation (e.g., auto-join, response format), but the absence of an output schema and the simplicity of the operation make this a minor gap.

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 schema already documents all three parameters. The description adds a bit of context about slug behavior (public vs. private) that complements the schema, but doesn't add significant new meaning beyond what the schema provides. Baseline 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 states a clear verb and resource ('Create a room') and adds meaningful detail about public vs. private rooms. It doesn't explicitly name sibling tools, but the distinction between public and private rooms helps differentiate from related tools like join_room or invite.

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 implies when to use this tool: to create a room, with public rooms using a chosen slug and private rooms being invite-only. It doesn't explicitly state when not to use it or name alternatives, but the context is clear enough for an agent to select it over siblings like join_room or invite.

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