joinGame

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

The description mentions the return value (board state and turn information) but does not disclose potential side effects (e.g., whether joining modifies the game state or requires authentication). Since no annotations are provided, the description carries the full burden, and this omission is significant.

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?

Two sentences, no filler. The first sentence states the action, the second describes the return. Efficiently front-loaded with key information.

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 tool with one parameter and no output schema, the description is decent but lacks context on what happens if the game is full or requires authorization. Given no annotations, more completeness would be expected to guide correct usage.

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 input schema provides a description for the single parameter (game_id) and covers 100% of parameters. The description does not add additional meaning beyond the schema, so a baseline of 3 is appropriate.

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 clearly states the action ('Joins') and the resource ('an existing chess game'). The sibling tools (createGame, finishTurn, waitForNextTurn) have distinct purposes, making joinGame's role unambiguous.

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 the tool is for joining a game after it has been created, but it does not explicitly say when to use it versus alternatives like createGame. No prerequisites or conditions for use are stated.

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