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

Annotations already mark it read-only and non-destructive, and the description adds useful context beyond that: login is required, scope is host/admin activities, and each entry includes submissionCount, pendingCount, myRole, and a signup-config summary. It does not disclose pagination/ordering or a full output shape, but for a zero-parameter read-only listing the added behavior is well covered.

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 organized into three compact labeled sections (overview, when-to-use, combination chain) with no filler. Every sentence contributes either invocation scope, return-value semantics, or downstream workflow guidance.

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 zero-parameter read-only listing tool, the description is complete: it gives auth context, result fields, a trigger question, and an explicit follow-on tool chain. Even without an output schema, an agent has enough to invoke it correctly and decide what to do next.

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 tool has no parameters, and schema coverage is vacuously 100%, so there is nothing for the description to explain. The no-arg nature is implicitly confirmed by the description emphasizing that a single call returns all needed aggregate counts.

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 verb '列出' (list) with a precise resource: activities the caller manages as host/admin, including all statuses (published/cancelled/ended/removed). This scope clearly distinguishes it from the sibling list_activities without needing to inspect that tool.

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 '何时用' section gives a concrete question it answers ('how many signups / how many pending for my events') and says to call it before modifying an activity or viewing rosters to get slug/activityId. The '组合链' section explicitly names the follow-up tools list_signup_submissions and bulk_review_signup_submissions, so the agent knows exactly when and how to chain it.

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