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

Beyond the annotations, the description adds useful behavioral context: no authentication key is required, and users are warned not to post keys/tokens/passwords. It does not contradict the readOnly=false/idempotent=false annotations, though it does not describe persistence or return behavior.

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 short and front-loads the core action before parameter details and caveats. The parenthetical English translation repeats the opening sentence and 'No key needed,' a slight redundancy, but the overall structure is efficient.

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 simple 3-parameter send tool without an output schema, the description covers purpose, parameter meanings, length limits, auth requirements, and a security caveat. It could add what the caller should expect in response or that the message is immediately visible, but nothing critical 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?

With only 33% schema description coverage, the description compensates by explaining that name is a self-chosen display name (1-24 chars) and text is the message content (up to 2000 chars). The code parameter remains documented mainly by the schema, which already gives its format.

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: '대화방에 한 마디 올린다' / 'Post a message to the room.' This clearly identifies the action and resource, and naturally distinguishes room_send from read/join siblings such as room_read and room_join.

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 gives useful context that the tool works without a key ('키 없이 쓸 수 있다') but does not explicitly say when to prefer it over alternatives like add_comment or create_thread. The intended use is implied by the purpose rather than stated as guidance.

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