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

Annotations declare write, non-idempotent, open-world, non-destructive; the description adds substantial beyond that: management-permission requirement, admin notification side effect, per-batch (≤20) and per-day (20) rate limits, and hard scope fences (no cross-activity/applicant/re-entry reuse, no audience expansion, no invites, no contact delivery). That is exactly the behavioral context an agent cannot infer from the flags.

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 permission/prerequisite tag is front-loaded and the sentences are maximally dense with no filler. It leans on bracketed shorthand and semicolon chains that make it harder to parse, but every clause conveys a real constraint or workflow step.

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 5-param mutation with no output schema, the description supplies the permission requirement, rate limits, scope limits, and the preview/confirm/re-confirm lifecycle. Only the meaning of note and activityRef is missing, which is minor for this tool.

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 coverage is 0%, so the description carries the full burden. It successfully explains preview's default, the previewHash confirmation handshake, and userIds' batching limit (≤20), but leaves note and activityRef entirely unexplained. Useful partial compensation, but two of five parameters remain undocumented in both places.

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 (申请/request) and resource (本场指定云成员的限期联系授权 – limited contact authorization for designated cloud members of this event), which is clearly distinct from review_activity_cloud_contacts and list_activity_cloud_contact_requests. It does not name a sibling alternative, so it sits just below the top band.

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?

Explicitly states the entry condition (needs management permission, notifies org admins) and prescribes the two-step flow: default preview, then re-call with the same params plus previewHash and preview=false, re-confirming on any change. It does not state when NOT to use it or point at sibling tools, so it stops short of a 5.

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