is_player_online

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

No annotations are provided, so the description carries the full behavioral burden. It only restates the operation and adds 'currently'; it does not disclose the return shape (e.g., boolean), latency, or behavior for invalid or nonexistent usernames.

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?

One sentence with no filler, front-loading the action and scope. This is appropriately concise for a tool with a single required parameter.

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?

With no annotations and no output schema, the description leaves the return type and the exact meaning of 'online' unstated. An agent can infer the call from the name, but the definition is not complete enough to fully understand the result.

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 for the bare 'username: string' parameter. It refers to 'a player' but never names the username parameter or clarifies format, case sensitivity, or error behavior, adding no meaningful parameter semantics.

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?

States a specific verb ('Check') and a precise resource ('if a player is currently online on Chess.com'), which is unique among the sibling tools. The purpose is immediately distinguishable from profile, stats, and games tools without needing the schema.

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 implies when to use the tool: any time a player's current presence status is needed. However, it does not explicitly state conditions, exclusions, or alternatives, so the guidance is only moderate.

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