Retrieve daily LINE follower statistics—followers, targeted reaches, and blocks—for a UTC+9 date, defaulting to yesterday; data is available after the day ends.
Follower statistics for one day: followers, targeted reaches, blocks. LINE computes these per day in UTC+9 and only after the day ends.
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | yyyyMMdd in UTC+9. Defaults to yesterday. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the UTC+9 day boundary and the eventual-availability lag (data only after the day ends), which is exactly the kind of non-obvious trait an agent needs. It says nothing about rate limits or auth, 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.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, front-loaded with the resource and metrics, followed by the temporal constraint. Every clause earns its place with no filler or repetition.
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?
With no output schema, the description compensates by listing the returned metrics and the day semantics. Combined with readOnly annotations and a single, fully documented parameter, an agent has everything needed to call it correctly and interpret when data is valid.
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% (the date param documents yyyyMMdd, UTC+9, and the yesterday default), so the schema carries the parameter burden. The description's mention of UTC+9 is consistent with the schema but adds no new syntax or format detail. Baseline 3 is correct when the schema already does the heavy lifting.
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 specific resource (follower statistics) and enumerates the exact metrics returned (followers, targeted reaches, blocks) scoped to a single day, which is far more concrete than a tautology. It does not explicitly contrast itself with the many sibling line_* tools, but the resource is distinctive enough that an agent can tell it apart from line_bot_info, line_get_profile, or line_message_quota.
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 states a meaningful usage constraint: the data is computed per day in UTC+9 and exists only after the day concludes, which tells the agent when results will and won't be available (e.g., today's data is not yet valid). It does not name alternative tools or exclusions, but for a single-purpose stats endpoint the availability window is the key guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.