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

Annotations only declare the mutation/open-world profile; the description goes well beyond them by disclosing login+organizer requirement, the confirmed=false default and its public-page consequence, the ≤30 per-activity cap, that avatars are self-filled, and crucially that this tool sends no notification. These are exactly the side effects an agent needs before calling a write tool.

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 【需要登录·主办方】 gating, then packs scope, defaults, limits, and the notification caveat into semicolon-delimited clauses with no filler. Dense but every clause carries actionable information.

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 non-idempotent write tool with no output schema, the description covers auth, side effects, limits, and non-notification behavior. The remaining gap is the return value (e.g. the created guestId), which would help a follow-up call but is minor for this operation.

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%, so the schema already documents all six parameters, including confirmed's intended meaning and userId's source. The description adds only the consequence of confirmed (default keeps the guest off the public page), a modest increment over structured data – baseline 3 is appropriate.

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 (add a guest to the activity lineup) and immediately delimits scope: '只新增嘉宾' only adds, and existing guestIds must not be duplicated or re-stated. It also names a sibling (create_guest_invite_link) so the agent can distinguish add-vs-invite without opening either 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?

Clear when-to-use (new guest, on-platform vs external) and an explicit when-not ('已有guestId勿重复/改状态'), plus routing to create_guest_invite_link for the notification path. It stops short of naming update_guest_candidates as the tool for an existing guest, leaving one alternative implicit.

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