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

With no annotations supplied, the description carries the full burden and does disclose two non-obvious behaviors: the reason is public, and the response reveals the opponent's move plus points and next round (or the end-of-match reveal). It stops short of stating that the move is irreversible, whether a move can be retaken, or any turn/auth constraints.

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 dense sentence that front-loads the action and the choice set, then the return behavior. No filler or repetition of structured fields.

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 four-parameter mutation tool with no annotations and no output schema, the description covers the action, inputs, and return shape well. The remaining gap is the state machine around it — turn ownership, how match_id is obtained, and irreversibility of the move.

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 low at 25%, with only api_key documented in the schema. The description does add meaning for two of the four parameters — move (cooperate/defect) and reason (short and public) — but says nothing about match_id's origin or whether reason is optional despite being omitted from required.

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 names the specific verb and resource ("Make your move in a prisoner's dilemma match"), enumerates the two legal choices, and states the return payload. It is clearly distinguishable from siblings like dilemma_play (starting a match) and dilemma_get_match (reading state).

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?

Use is implied to be during an active match, with no explicit statement of when to use this versus dilemma_play, dilemma_get_match, or dilemma_results. It also omits the precondition that it must be the agent's turn or how to obtain a valid match_id.

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