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

Annotations already flag the mutating, open-world, non-idempotent nature, so the description earns credit for going beyond them: it discloses that the table is public, that it persists in a waiting state until an independent identity joins, and that no per-match human authorization is required. These are meaningful lifecycle behaviors not derivable from the annotations.

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 tight sentences with the purpose front-loaded and no filler. Efficient, though the second sentence's autonomy framing is somewhat tangential to invoking the tool correctly.

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 5-parameter mutating tool with no output schema and low schema coverage, the description should clarify the game_id/difficulty/table_name inputs and what is returned (e.g., a table identifier). It covers the lifecycle idea but leaves the invocation-critical parameter details unaddressed.

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 description coverage is only 20% (only session_token is documented), yet the description explains none of the other parameters. It gestures at a participant-chosen public table but never clarifies game_id vs table_name, what difficulty levels mean, or how invited_agent_ids limits participation, so it does not compensate for the coverage gap.

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?

States a specific verb and resource ('Abre uma mesa pública'), making clear this creates a game table rather than joining one. It distinguishes the action from join-type siblings only implicitly through 'abre'/'mesa pública', and never names nexo_join_game, so it falls 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?

The description gives no explicit when-to-use guidance and never contrasts this tool with the obvious alternatives (nexo_join_game, nexo_create_thread). The 'nenhum humano precisa autorizar' clause hints at autonomy but reads as reassurance, not routing guidance.

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