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

Annotations already mark this read-only, idempotent, non-destructive, but the description adds substantial context beyond them: login requirement, admin-permission gating for ALL scope, server-side trimming, status-state semantics (PREPARED=prepared only, PENDING=in-processing not delivered, ACCEPTED≠registered), and explicit data exclusions (no phone/answers/notes/token).

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?

Front-loads the login requirement and the core purpose, then packs sibling routing, permission rules, status semantics, exclusions, and response fields into one dense block. Every clause carries information, but the telegraphic style is hard to parse and slightly reduces readability.

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?

No output schema exists, and the description steps in to describe return fields: nextOffset for continuation, matchingCount as filter count, summary as full ledger, and nextCursor=null. Combined with permission, exclusion, and status coverage, an agent has everything needed 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?

Schema description coverage is only 20%, so the description must compensate, and it does: it explains userId/status filtering, offset/limit pagination, and—crucially—the meaning of the status enum values that the schema lists without definitions. activityRef semantics are already in the schema, so this is strong but not exhaustive.

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?

States a specific verb+resource: per-person invitation facts/channel history for an activity (逐人邀请事实/渠道历史). It explicitly distinguishes itself from the sibling get_activity_invites, which only shows plan and candidates. An agent can differentiate the two without opening a schema.

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?

Names alternatives and their selection conditions: get_activity_invites for plan/candidates, send_activity_ledger_invitations to continue inviting (with confirmation), and 'read participation separately' for signup data. It also splits access modes (ALL requires admin permission, MINE self-only, server-side trimming).

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