steam-mcp

steam_get_player_trend

Retrieve player-count history for a Steam game, including min/max/average, week-over-week change, and an insight line; requesting an untracked game starts tracking it.

Instructions

Player-count history for a game: snapshot series with min/max/average, week-over-week change, and a generated insight line. Steam itself provides no history — this data is collected by the companion backend over time. Requesting a trend for an untracked game starts tracking it.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "app": "<app>"
    },
    "name": "steam_get_player_trend"
  }
}

Input Schema

Name	Required	Description	Default
`app`	Yes	AppID (e.g. "730") or exact game name. Prefer an AppID from steam_search_apps for ambiguous names.
`days`	No	How far back the series goes.

Output Schema

Name	Required	Description	Default
`days`	Yes
`note`	No
`appid`	Yes
`stats`	No
`points`	Yes
`insight`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 13, 2026

TDQS

A4/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does substantial work: it discloses that Steam provides no history and the data comes from a companion backend over time (implying sparse history for newly tracked apps), plus the side effect that querying an untracked game begins tracking it. It omits auth requirements and whether tracking can be stopped, keeping it short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, zero filler: purpose first, then the provenance caveat, then the side effect. Each sentence delivers information the agent cannot get from the schema or annotations.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so the return shape need not be explained (the description's output enumeration is mild redundancy). The critical unknowns – data provenance and the tracking side effect – are covered, leaving only minor gaps such as what a series looks like for a barely-tracked app.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% – the schema already explains the AppID/name format for 'app' and the lookback meaning of 'days'. The description adds no parameter-level syntax or defaults beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific resource and verb-equivalent: 'Player-count history for a game,' and enumerates the exact outputs (snapshot series with min/max/average, week-over-week change, insight line). This is unmistakably distinct from siblings like steam_get_market_pulse or steam_get_app_reviews without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the resource name, and one triggering condition is given ('requesting a trend for an untracked game starts tracking it'). However, it never states when to prefer this over a sibling such as steam_get_market_pulse for current player numbers, so the agent must infer the choice.

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

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