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

The description adds substantial behavioral context beyond the annotations: unknown metadata is treated as unknown rather than 'no', party size uses canonical co-op group data and never session/server capacity, and only positive evidence is used for crossplay and play-together modes. It also discloses result fields and source attribution requirements, which is genuinely useful for safe invocation.

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?

The description is dense but every sentence earns its place: it defines scope, clarifies data semantics, states the unknown-handling policy, and explains result field expectations. It is front-loaded with the core purpose before moving into constraints.

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?

The description covers the key semantic pitfalls, result source identification, link behavior, and the tool's non-destructive read-only nature. With an output schema already present, the description does not need to repeat return values, and nothing critical is missing for correct invocation.

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?

Although schema coverage is 100%, the description adds critical disambiguation that the schema alone does not convey, such as platform meaning availability rather than crossplay, players meaning canonical group size rather than server capacity, and play_together requiring confirmed positive evidence. This materially helps an agent choose correct parameter values.

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 clearly states the tool finds published co-op games from Co-Op Now matching a concrete co-op intent, and enumerates the filtering dimensions: party size, play mode, platform, crossplay evidence, and session length. This distinguishes it from the broader search_games or focused get_game siblings without needing to open the schema.

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 clear context for when to use the tool: when the user has a concrete co-op intent such as exact party size, play-together mode, platform, crossplay, or session length. It does not explicitly name alternative tools or state when not to use it, so it stops 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.