Get Group Member Count

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

No annotations are provided, so the description carries the full burden. It discloses the membership requirement, which is a behavioral constraint. However, it does not describe what happens if the bot is not a member (e.g., error), nor the return format (an integer count). For a simple read operation, this is adequate but not rich. It adds the key prerequisite beyond what the schema provides.

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 description is two concise sentences with no filler. The core purpose is front-loaded, and the prerequisite follows naturally. Every word earns its place; it is appropriately sized for a simple one-parameter tool.

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?

Given the tool's simplicity, the description covers the essential aspects: what it returns (count), the resource (group chat), and a key prerequisite (bot membership). It does not explicitly state the return type or error handling, but these are largely inferable. The single parameter is fully documented in the schema. No output schema exists, so the description could mention the return value, but the name implies an integer. Overall, it is sufficient for an agent to call it correctly.

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 description for groupId already covers the parameter semantics: 'LINE Group ID (starts with "C")'. The tool description adds no additional parameter detail. Since schema coverage is 100%, the baseline of 3 applies – the description does not need to compensate, but also adds no value beyond the schema.

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 the specific verb 'Get' and the resource 'number of members in a LINE group chat', which clearly distinguishes it from siblings like get_group_member_ids (which lists IDs) and get_room_member_count (which targets rooms). The purpose is unambiguous and action-oriented.

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?

The description includes a clear prerequisite: 'The bot must be a member of the group.' This guides when the tool can be used. While it doesn't explicitly contrast with alternatives, the group vs. room distinction is implicit in the name and description, so agents can infer when to select it. The condition adds practical usage context.

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