room_join

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

With no annotations, the description fully discloses a critical side effect: 'Joining a different room closes the previous WebSocket and fails its pending acknowledgements.' It also mentions the opening of a WebSocket connection, which is an operational trait. While it doesn't cover all edge cases (e.g., permissions, token errors), it goes beyond a generic statement and informs the agent of a destructive consequence.

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?

The description is three sentences, each serving a distinct purpose: (1) states the core function, (2) gives usage order and parameter requirements, (3) warns of side effects and suggests an alternative. There is no fluff, and the most important information is front-loaded.

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?

Given the tool's moderate complexity, the description covers the purpose, sequencing, parameter conditions, and a key side effect. The presence of an output schema means return values are not required in the description. It could mention error scenarios (e.g., invalid room_id) but that is not essential for an agent to invoke it correctly.

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?

The description adds meaning to the parameters by explaining that room_id is the only required field for public rooms and token is conditionally required for private rooms. Since the schema description coverage is low (0% per context signals), this compensation is valuable. The schema itself only lists a token description in Indonesian, so the English explanation clarifies the use case.

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 uses the specific verb 'Join' with the object 'existing room' and specifies 'open its Cloudflare WebSocket connection', clearly distinguishing it from sibling tools like room_create (create) and room_info (info). It also notes the requirement of being an existing room, which further separates it from creation tools.

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 provides explicit sequencing ('Call after agent_register'), clarifies parameter conditions ('public rooms need only room_id, while private rooms require the owner's token'), and explicitly names an alternative ('use room_info') when replacing an active connection. This gives a clear when-to-use and what-to-check-before-use guidance.

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