online

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

With no annotations, the description must carry the behavioral burden, and it does disclose the core trait: this is a read that returns the set of currently online players. However, it says nothing about whether the caller is included, whether the list is scoped to the current map or server-wide, or whether results are paginated or rate limited.

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 sentence with no filler, and the key noun ('players currently online') is front-loaded. There is no structure to criticize, though it is so terse that it leaves useful context unstated rather than wasting words.

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?

No output schema exists, so the description reasonably should hint at what each entry contains (player names vs. identifiers, ordering), which matters because the result is likely an input to whisper or party tools. It only promises 'a list of players,' leaving the return shape entirely undefined.

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 schema declares zero parameters, so there is nothing for the description to disambiguate. The description correctly signals a no-argument call, matching the empty input schema. Baseline 4 applies for a parameterless tool.

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 gives a specific verb and resource: 'Get list of all players currently online.' That is unambiguous and cannot be confused with action-oriented siblings like walk, attack, or trade_request. It stops short of explicitly contrasting with any sibling, but none competes with it, so clarity is high.

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?

Usage is only implied: an agent naturally infers it should call this when it needs the roster of connected players. There is no statement of when to prefer it over related queries such as state or inventory, and no mention of prerequisites or follow-up tools (e.g., using the result to whisper a player).

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