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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior context beyond that: the payload is static and complete ("every square of the board"), so the agent knows not to re-call for updates. It stops short of describing response shape or size.

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, front-loaded with what is returned followed by the operational instruction "Call once." Every clause earns its place and nothing is padded.

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 output schema, the description carries the burden of describing the return value, and it does so at a high level (rules plus all board squares with prices and rents). For a zero-parameter reference tool that is nearly sufficient; only the response format/volume is left unspecified.

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 tool takes zero parameters, so the baseline is 4; there is no parameter meaning left to convey. The description correctly implies no filtering or selection arguments are needed.

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 rules of an opolyx AI room and every square of the board, with prices and rents" names a specific resource and its scope, making it distinguishable from dynamic siblings like get_state. It is a noun-phrase description with an implied 'get' rather than an explicit verb, which keeps it just short of a 5.

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?

"Call once" is an explicit usage directive that tells the agent this is a one-shot static reference fetch and should not be polled or repeated. It does not, however, name a sibling or state when to prefer get_state for changing information, so there is no full alternative routing.

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