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

With no annotations provided, the description carries the full disclosure burden, but it reveals only that the tool performs a computation. It does not state whether invalid FENs are rejected, what the returned move looks like (SAN, UCI, from-to squares), whether it returns a legal or an optimal move, or any side effects or limits.

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 wasted words, and the resource ('Chess Move') is front-loaded ahead of the verb phrase. It loses a point because the 'Chess Move:' prefix largely restates the tool name and because the terseness comes at the cost of omitting all operational guidance.

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?

Despite having four unconstrained string parameters, zero required fields, no output schema, and no annotations, the description leaves all disambiguation to inference. An agent cannot determine which parameter combination to pass, what notation the move will be returned in, or what happens with an invalid position — exactly the gaps that matter for a game-engine tool.

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?

Although schema coverage is 100%, the parameter descriptions are tautological ('Fen to process', 'Side to process', 'Board to process', 'Color to process') and add no meaning beyond the parameter names. The tool description does not clarify the confusing overlap between fen/board and side/color, leaving an agent unable to determine which parameters are needed and how they relate.

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 — 'Compute a chess move for a given board' — and the 'Chess' qualifier distinguishes it from game siblings like x402-2048-move, x402-reversi-move, and x402-connect4-move. It loses full marks because 'compute a move' is ambiguous (generate a recommendation vs. validate/apply a move) and because the redundant inputs (fen vs board, side vs color) are never reconciled.

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?

No guidance is given on when to use this tool, which alternative to prefer, or which input combination is required. The description does not even hint at when to choose this over sibling game-move tools, nor does it explain whether fen or board (and side or color) should be supplied, so an agent must guess the call contract.

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