Retrieve a user's activity statistics over a specified number of days, including totals, active days, daily averages, activity types, and last activity date.
获取用户活跃度统计（近 N 天）。
Args:
user_id: 用户 ID（默认 local）
days: 统计窗口天数，默认 30
Returns:
{exists, stats: {total, active_days, daily_avg, by_type, last_activity_at, active_date_list}}
| Name | Required | Description | Default |
|---|---|---|---|
| days | No | ||
| user_id | No | local |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose the parameter defaults and the exact return structure (exists, stats.total, active_days, daily_avg, by_type, etc.), which is genuinely useful. However, it never states that this is a read-only operation, nor mentions permissions, rate limits, or behavior when a user has no activity.
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 purpose is front-loaded in the first line, followed by compact Args and Returns blocks. Every element earns its place 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?
There is no output schema, but the description supplies a Returns block listing the exact response fields, covering the return-value gap. For a two-parameter read tool with no annotations, this is largely complete, missing only explicit read-only/edge-case disclosure.
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 0%, so the description must compensate, and it does: it documents both parameters with meaning and defaults ('user_id: 用户 ID（默认 local）', 'days: 统计窗口天数，默认 30'). The only gap is the absence of accepted ranges or formats for days.
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 and resource: '获取用户活跃度统计（近 N 天）' (get user activity statistics over the last N days). This is clearly distinguishable from siblings like user_get_profile or user_get_retention, though it never explicitly names a sibling to route between them.
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 when-to-use guidance, no prerequisites, and no mention of alternatives such as user_get_profile or user_get_retention. The agent is left to infer when activity stats are the right call.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.