Find which of your Steam friends own a specific game. Check their libraries to see who you can play with, or filter to see who is currently playing now.
List which of a user's friends own (or are playing) a specific game — "who can I play X with" (about friends' libraries, not store search).
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Changes observed during successful MCP inspections.
v1.18.0Input schema / $defs / FriendsWhoOwnInput / properties / appid / titleRemoved value: -"Appid"Input schema / $defs / FriendsWhoOwnInput / properties / limit / titleRemoved value: -"Limit"Input schema / $defs / FriendsWhoOwnInput / properties / max_friends / titleRemoved value: -"Max Friends"Input schema / $defs / FriendsWhoOwnInput / properties / playing_now / titleRemoved value: -"Playing Now"Input schema / $defs / FriendsWhoOwnInput / properties / response_format / $refRemoved value: -"#/$defs/ResponseFormat"Input schema / $defs / FriendsWhoOwnInput / properties / response_format / enumAdded value: +[
+ "markdown",
+ "json"
+]Input schema / $defs / FriendsWhoOwnInput / properties / response_format / typeAdded value: +"string"Input schema / $defs / FriendsWhoOwnInput / properties / steamid / defaultRemoved value: -nullInput schema / $defs / FriendsWhoOwnInput / properties / steamid / titleRemoved value: -"Steamid"Input schema / $defs / FriendsWhoOwnInput / titleRemoved value: -"FriendsWhoOwnInput"Input schema / $defs / ResponseFormatRemoved value: -{
- "description": "Output format for tool responses.",
- "enum": [
- "markdown",
- "json"
- ],
- "title": "ResponseFormat",
- "type": "string"
-}Input schema / titleRemoved value: -"steam_find_friends_who_ownArguments"Output schema / (root)Previous value: -{
- "properties": {
- "result": {
- "title": "Result",
- "type": "string"
- }
- },
- "required": [
- "result"
- ],
- "title": "steam_find_friends_who_ownOutput",
- "type": "object"
-}New value: +nullv1.14.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the description does not need to repeat safety. It adds the scope clarification (friends' libraries vs store search) but does not disclose potential performance/rate-limit implications of checking many friends, which the schema notes. It is not contradictory and adds some context.
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 sentence with no fluff; the key action is front-loaded, and the clarifying note about store search is useful.
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 a clear purpose and annotated read-only, the description provides the essential 'who can I play with' context, but does not mention output format (though 'List' implies a list) or that it may make multiple lookups. It is largely complete given the schema.
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 schema includes full descriptions for each parameter (appid, limit, steamid, max_friends, playing_now, response_format), so schema coverage is high. The description does not elaborate on parameters, so it adds no extra semantics; baseline 3 is appropriate.
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 (List) and resource (which of a user's friends own a game), and clarifies it is about friends' libraries not store search, distinguishing it from search tools. It is clear and unambiguous.
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?
It implies the usage context 'who can I play X with' and explicitly excludes store search, providing clear context. However, it does not name alternative sibling tools like steam_get_friend_list or state when not to use it, so it lacks explicit exclusions beyond store search.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.