Open or reopen a room

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

Annotations cover the safety profile (idempotentHint=true, readOnlyHint=false), and the description adds genuinely new behavior: the already-open room is returned unchanged, the exact failure code room_limit_reached, and the required rooms:write scope. This is richer than the annotations alone.

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 core action and idempotent behavior, then usage, then failure/auth notes. It is dense and semicolon-heavy in the first clause, but 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?

With no output schema, the description states the return value ('the room and its links'), the error path, and the required permission scope. Nothing an agent needs to invoke this correctly is missing.

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?

Only one parameter, and schema coverage is 100% with a pattern and example already documented, so the schema carries the load. The description adds no syntax or format detail for 'code', making the baseline 3 correct.

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 precise verb+resource pair ('Open a prepared room, or reopen a closed one') and clarifies the state distinction between prepared/closed/already-open. An agent can distinguish this from close_room and create_room without opening any schema.

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?

Explicitly names the preceding call ('after create_room with open=false') and the alternate use case ('to resume a session'). It also names close_room as the remedy when room_limit_reached occurs, giving a complete when-to-use and what-to-do-next path.

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