Find co-op games you and your friends already own to plan a game night, or discover new co-op titles your group can buy and play together.
Find co-op games the host and their friends all own — for game night.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Changes observed during successful MCP inspections.
v1.18.0Input schema / $defs / PlanCoopNightInput / properties / country_code / titleRemoved value: -"Country Code"Input schema / $defs / PlanCoopNightInput / properties / friends / titleRemoved value: -"Friends"Input schema / $defs / PlanCoopNightInput / properties / limit / titleRemoved value: -"Limit"Input schema / $defs / PlanCoopNightInput / properties / max_friends / titleRemoved value: -"Max Friends"Input schema / $defs / PlanCoopNightInput / properties / min_friends_owning / titleRemoved value: -"Min Friends Owning"Input schema / $defs / PlanCoopNightInput / properties / mode / titleRemoved value: -"Mode"Input schema / $defs / PlanCoopNightInput / properties / online_only / titleRemoved value: -"Online Only"Input schema / $defs / PlanCoopNightInput / properties / response_format / $refRemoved value: -"#/$defs/ResponseFormat"Input schema / $defs / PlanCoopNightInput / properties / response_format / enumAdded value: +[
+ "markdown",
+ "json"
+]Input schema / $defs / PlanCoopNightInput / properties / response_format / typeAdded value: +"string"Input schema / $defs / PlanCoopNightInput / properties / steamid / defaultRemoved value: -nullInput schema / $defs / PlanCoopNightInput / properties / steamid / titleRemoved value: -"Steamid"Input schema / $defs / PlanCoopNightInput / titleRemoved value: -"PlanCoopNightInput"Input schema / $defs / ResponseFormatRemoved value: -{
- "description": "Output format for tool responses.",
- "enum": [
- "markdown",
- "json"
- ],
- "title": "ResponseFormat",
- "type": "string"
-}Input schema / titleRemoved value: -"steam_plan_coop_nightArguments"Output schema / (root)Previous value: -{
- "properties": {
- "result": {
- "title": "Result",
- "type": "string"
- }
- },
- "required": [
- "result"
- ],
- "title": "steam_plan_coop_nightOutput",
- "type": "object"
-}New value: +nullv1.14.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
readOnlyHint already signals a safe read, and the description's 'find' aligns with it. However, the description does not disclose the tool's dual modes (owned vs new), the fact that it can derive a group from the host's online friends, or that it ranks suggestions by ownership count.
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?
One front-loaded sentence with no filler. It loses a point because the curt phrasing ('all own') obscures the 'new' mode, so brevity comes at some cost to accuracy.
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 tool with multiple modes, optional friend derivation, and custom output format, a single sentence is thin. The rich parameter schema covers the mechanics, but the description still omits the alternate 'new' mode and gives no sense of the returned artifact.
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?
The tool description contributes the group-ownership concept, which relates to steamid/friends/min_friends_owning, but it maps no parameters explicitly. The nested schema is already well-documented, so the description only modestly adds meaning.
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 names a concrete resource (co-op games) and the condition (owned by host and friends), making the default 'owned' mode identifiable. It is less specific about the 'new' mode (suggesting games nobody owns) and does not name a sibling, so it is not 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?
There is no explicit guidance about when to prefer this over siblings like steam_find_friends_who_own or steam_compare_games. The 'for game night' phrase implies a social use case, but it never states prerequisites, when to supply an explicit friends list, or when to use owned vs new mode.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.