join

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

With no annotations, the description carries the full burden and does well: it discloses ownership semantics ('takes ownership'), the existence of waiter state, and the once-per-connection contract. Remaining ambiguity (what 'waiter state' means, what happens on conflict) keeps it short of 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 tight sentences: the first front-loads purpose and return contents, the second carries the invocation contract. Dense but every clause earns its place; minor awkwardness in 'start command exactly once when waiter is missing.'

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 an annotation-free tool with no output schema, the description covers what it returns and the critical call-once/ownership behavior, which is what an agent needs to avoid misusing a coordination primitive. Only the parameter semantics gap leaves it imperfect.

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 0%, so the description must compensate, but it only re-uses the words 'room' and 'name' without defining their format, uniqueness, or role. The two required parameters remain effectively undocumented.

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+resource ('Join a room') and even enumerates what the call returns (identity, participants, waiter state, command, launch instructions). The verb 'join' is self-evidently distinct from the sibling actions send/rename/leave, though no sibling is named explicitly.

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?

It gives concrete when-to-call guidance: invoke once per new MCP connection, and 'start command exactly once when waiter is missing.' This is rarer and more actionable than generic usage text, though it never contrasts with the sibling tools or states when NOT to call.

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