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

With no annotations, the description carries the full burden and does reasonably well: it discloses the slug+flag request syntax (e.g. 'slug+flag') and that results feed play_create_game. It stops short of stating read-only behavior, pagination, or error handling for unknown families.

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?

Three short sentences, no filler, and the purpose is front-loaded before the follow-up usage and syntax notes. Every sentence adds a distinct piece of 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 one-parameter list tool with 100% schema coverage and no output schema, the description covers purpose, the format of returned variant slugs, and the downstream consumer. Additional detail on result ordering or invalid-family behavior would make it fully complete.

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 single 'family' parameter is 100% documented in the schema with a full enum-like value list, so the schema does the heavy lifting. The description adds only the optional flag-suffix syntax, which is a return-value convention rather than parameter meaning. Baseline 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?

Names a specific verb and resource ('List available variants for a game family'), so the agent knows exactly what comes back. It does not, however, distinguish itself from near-siblings like play_list_families, chess_list_variants, or rules_get_variant_list, which list related things.

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 clear downstream context: 'Each variant can be passed to play_create_game', which tells the agent when this tool is the right first step. It offers no explicit when-not guidance or naming of alternative listing tools, so it falls short of a 5.

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