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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds significant behavioral context beyond annotations: clarifies that speakers line has full data while audience line only has counts (no roster), that openInvite is included in the response, and that contacts are not directly provided (only hasContacts and conversationId for start_conversation). This enriches agent understanding of data semantics and constraints.

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 structured with clear sections (需要登录·主办方, 何时用, 组合链, 口径), front-loading the purpose and usage. Every sentence earns its place, covering key behavioral caveats and follow-up actions without waste. It is dense but well-organized for an agent to parse quickly.

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?

Since there is no output schema, the description must convey what the tool returns, and it does: status and stats for both plans, candidate lineup details, audience invitation counts, and external link. It also specifies what is not included (contacts, audience roster) and how to proceed (conversationId for start_conversation). This is sufficient for correct invocation and expectation setting.

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?

There is only one parameter, activityRef, and the schema description already covers it fully (activity slug or id, with reference to list_my_activities / get_organizer_activity). The tool description does not add parameter-specific details beyond that, which is acceptable given 100% schema coverage. Baseline 3 applies.

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 explicitly states the tool reads the full guest invitation picture for an activity, listing the two plans (SPEAKER and ATTENDEE), candidate lineup, audience counts, and external link. It clearly distinguishes from siblings like update_guest_candidates and set_guest_invite_plan_status by naming them in the combination chain. The verb 'get' and resource 'activity invites' are specific.

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?

Provides explicit when-to-use guidance ('when asking how far guest invites are or who accepted'), a combination chain showing when to use other tools (update_guest_candidates, set_guest_invite_plan_status, send_guest_invite_now), and a when-not-to-use note (don't call create_guest_open_link because openInvite is already in the response). This fully routes the agent.

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