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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful polling behavior by noting messages newer than a cursor and returning a cursor, but it omits error behavior, auth requirements, and the shape of returned messages.

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?

A single front-loaded sentence with no wasted words. The core action and polling instruction are immediately visible.

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 three-parameter polling tool with no output schema and no schema descriptions, the definition is under-specified. It does not explain how to obtain the initial cursor, what 'limit' does, or how returned messages and cursors are structured.

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 carry parameter meaning. It only loosely explains 'since' as a cursor and says nothing about 'room' format or what 'limit' controls.

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 states a specific verb and resource: read room messages newer than a cursor. It is clear what the tool does, but it does not distinguish itself from siblings such as lobby_inbox or lobby_rooms.

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 phrase 'poll with the returned cursor' gives implied usage guidance for repeated polling. However, it does not say when to use this tool instead of lobby_inbox, lobby_rooms, or other lobby siblings.

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