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

Annotations already mark the tool as read-only and idempotent, and the description adds meaningful behavioral context: co-op capacities are reported as distinct fields, the result includes source, canonical_url, and UTM-tagged open_url, and the agent should attribute Co-Op Now and include the co-op.now link when links/citations are supported. This goes beyond schema or 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?

The description is compact and front-loaded with the core action, followed by two sentences that add high-value behavioral and output details. Every sentence earns its place, and there is no redundant or filler content.

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?

Given one required parameter, full schema coverage, a read-only/idempotent annotation set, and an output schema, the description covers what an agent needs to invoke the tool correctly. It adds workflow context, key output distinctions, and link/citation handling, so nothing critical is missing.

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% and the only parameter, id, is already described in the schema as coming from search_games or find_coop_games. The description repeats this provenance but adds no new semantic details about format, constraints, or behavior related to the parameter.

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 action ('Fetch full public details') and the resource ('one Co-Op Now catalog game by id'), and it names the source tools (search_games or find_coop_games), which distinguishes this tool from the sibling search/find tools. An agent can immediately understand this is a detail-by-id tool rather than a discovery tool.

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 indicates when to use the tool: after obtaining an id from search_games or find_coop_games. This positions it in a clear workflow against its siblings, though it does not explicitly state 'use find_coop_games/search_games instead when you need a list' or list exclusion conditions.

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