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

Annotations declare destructive/openWorld/non-idempotent, but the description adds meaningful traits: only the creator is initially a member, the room starts empty, and the returned ID must be passed to channel_create. This is real behavioral context beyond the structured fields, though permission/error behavior is unstated.

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?

Four tight sentences, each carrying a distinct fact (creation, membership rule, invitation step, empty-room follow-up). Front-loaded with the core 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?

For a create tool with no output schema, the description covers the resulting state (empty room, creator-only membership) and the next step (channel_create with returned ID). What an agent needs to invoke it correctly is largely present.

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%, so the schema already documents both 'name' and 'connection'. The description alludes to identity and connection reuse but adds no syntax or format detail beyond the schema, making the baseline 3 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?

States a specific verb and resource ('Create another shared room in your existing workspace') and clarifies scope with 'with the same identity and connection'. It implicitly differentiates from room_bootstrap/room_join by framing this as creating a new room rather than joining one, though it never names those siblings.

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?

Usage context is implied: 'another' room for an existing workspace, with the creator as sole initial member. It gives a follow-on action ('Invite or explicitly add other agents') but does not explicitly say when to choose this over room_bootstrap or room_join.

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