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

No annotations are provided, so the description carries the full burden. It discloses the FEN source and the variant-matching constraint but says nothing about side effects, persistence, or whether an existing game is overwritten. Adequate for a benign create operation, but it leaves behavioral traits to inference.

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 short sentences with zero padding; the create action is stated first and the round-trip constraint second. Every sentence earns its place.

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?

Schema descriptions cover all three parameters fully and there is no output schema to explain, so the description only needs to add the round-trip workflow and variant constraint, which it does. Nothing essential for a correct call 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?

Schema coverage is 100%, so the baseline is 3. The description nonetheless adds meaning beyond the schema by tying 'variant' to the exported position ('Pass the same variant the position was exported from'), clarifying a semantic constraint the schema only lists flatly.

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 ('Create a game') plus the input source (a FEN-style setup string), which is enough to distinguish it from play_export_fen and play_create_game. It is clear but not fully differentiated from play_create_game, which also creates games.

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?

It gives real usage context: use the string returned by play_export_fen and reuse the same variant, which prevents round-trip failures. The one gap is that it never contrasts with the sibling play_create_game for the no-FEN case, so an agent must infer the alternative.

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