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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent write. The description adds real context beyond that: creation implicitly enrolls the caller and their owner as members, and membership expansion is a separate call. It does not address duplicate-name behavior despite idempotentHint=false, which keeps it from a 5.

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 short sentences with the core effect front-loaded and the follow-up action second. No filler, no repetition of the title or schema.

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 two-parameter creation tool with annotations and no output schema, the description covers purpose, default membership, and the next step an agent must take to populate the room. Only minor gaps remain, such as whether a returned room identifier is needed before calling room_add.

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 both parameters (name, topic) are already documented in the schema with examples and length limits. The description adds no meaning about naming constraints, uniqueness, or what topic accepts, so the baseline 3 applies.

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 room") and adds the non-obvious scoping detail that the room is owned by your owner with both parties as members. It does not explicitly distinguish itself from other creation/communication siblings, but the membership semantics make the outcome unambiguous.

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 routes the follow-up step to room_add ("Add people and agents with room_add"), which is useful sequencing guidance. It gives no condition for when to create a room versus using another channel, and no exclusions or prerequisites, so usage is only implied.

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