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

Annotations already cover readOnly/idempotent/non-destructive/closed-world, so the bar is lower. The description still adds real value beyond them: the result cap (up to 8), the filter constraint ('only returns games that fit the group size'), the returned fields (player counts and links), and the boundary that it does not launch a game.

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?

Front-loads the trigger conditions, then behavior and the negative boundary in three tight sentences with no filler. The first sentence is a long comma-separated list, which is slightly unwieldy but still purposeful.

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 an output schema present and 100% schema coverage, the description need not explain return values, and it correctly focuses on triggers and scoping. Annotations cover safety, so the only mild gap is the absence of sibling differentiation for disambiguating against search_games and plan_game_night.

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 100% with enums documented for vibe and locale, so the schema already carries parameter semantics. The description only echoes 'number of players (and optionally the mood)' without adding format or constraint detail, matching the baseline 3 when structured fields do the heavy lifting.

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+resource (recommend games) and adds scope: returns up to 8 matching PadConsole games with player counts and links, filtered to group size. Clear and concrete, but it never names or contrasts with the siblings (search_games, plan_game_night), so the agent must infer the boundary from context alone.

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?

Opens with an explicit 'Use this when...' clause enumerating concrete trigger scenarios (friends/family/kids, TV without console, phone-as-controller party games, remote play). This is strong when-to-use guidance, but it offers no named alternatives or explicit when-not conditions beyond the closing 'Does not start a game.'

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