Co-Op Now

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.

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.

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds meaningful behavior beyond that: it discloses the exact link fields (canonical_url and UTM-tagged open_url), the source field, and the distinction between item-level and response-level attribution for picks without a game id.

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 core purpose is front-loaded in the first clause, followed by dense, relevant detail about links and source attribution. It is slightly run-on but every clause contributes useful information with no filler.

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, read-only, idempotent tool with an output schema, the description covers purpose, source, link fields, and an attribution edge case. It does not mention ordering or how 'underrated' is determined, but nothing essential is missing for correct usage.

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 coverage is 100%; the input schema already fully documents the only parameter, limit, including its default, minimum, and maximum. The description adds no additional parameter-level meaning, so the baseline of 3 applies.

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 uses a specific verb and resource: it returns community-picked underrated co-op games from Co-Op Now's Hidden Gems list. This clearly differentiates it from the more general sibling tools search_games, find_coop_games, and get_game.

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 makes the tool's domain clear: it is for retrieving curated hidden-gem co-op games from a specific source. It also gives a concrete behavioral instruction about including the co-op.now link when the client supports links or citations, though it does not explicitly name sibling alternatives or exclusions.

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

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

Annotations already mark the tool as readOnly, idempotent, and non-destructive. The description goes beyond this by disclosing output characteristics: canonical co-op party size distinct from server capacity, a UTM-tagged open_url, and source attribution. This adds meaningful context about what the tool returns and how the output should be used.

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 front-loaded with its core purpose and stays free of filler. The middle sentence packs several output fields and a citation instruction into one long clause, but every element serves a purpose, so the overall structure is still efficient.

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 read-only, two-parameter search tool, the description covers the purpose, key return fields, citation behavior, and when to choose the alternative sibling. An output schema exists to supply any remaining structural detail, 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%, with both query and limit already documented. The description adds no additional parameter-level meaning beyond restating that lookups are by title. Baseline 3 is appropriate because the schema carries the parameter semantics.

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 states a specific verb ('Look up') and a clear resource ('games by title in Co-Op Now's public co-op catalog'). It also distinguishes the tool from find_coop_games by noting that the latter handles structured discovery by party size, play mode, platform, or session length.

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 explicitly directs agents to use find_coop_games when searching by structured attributes, establishing a clear when-not condition. It also gives actionable usage guidance by instructing the agent to cite Co-Op Now and include the co-op.now link when the client supports links or citations.

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