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

The only annotation is idempotentHint, so the description carries most of the burden and does well: it discloses the login/organizer auth requirement, the real-world side effect (one private message per person on an interval), that pausing is always available, and the rejection conditions. It stops short of saying what happens to already-dispatched messages on pause or whether start after pause resumes the remaining roster.

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?

It is dense but front-loaded: auth and action semantics come first, then the confirmation workflow, then the rejection rules. Semicolon-separated clauses keep it short, though a few fragments (e.g. the SPEAKER clause) are compressed to the point of ambiguity.

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?

There is no output schema and the description still covers the things an agent actually needs for a side-effecting mutation: authorization, mandatory user confirmation before dispatch, cadence of outgoing messages, pause availability, and every stated refusal condition. The only remaining gap, resume behavior after pause, is minor against an otherwise complete operational picture.

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 33% (only activityRef is documented), so the description needs to compensate. It adds useful semantics for action (start dispatches per interval, pause halts) and for role (SPEAKER with a still-generating state is rejected), but the phrase about SPEAKER is terse and ambiguous, and intervalMinutes is referenced without being a parameter of this tool, which can confuse the reader about where it comes from.

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 names a specific verb pair (start 起跑 / pause 停止) applied to a specific resource (the guest invite plan), so an agent can tell it is a state-setter rather than a sender. It does not explicitly differentiate itself from the sibling set_guest_invite_plan (which apparently carries intervalMinutes), leaving the boundary between configuring a plan and running it implicit.

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?

It spells out the full workflow: verify the roster with get_activity_invites and read it aloud to the user for confirmation before starting, then start sends one DM per intervalMinutes and may be paused at any time. It also states when the call will be rejected (SPEAKER still generating, zero registered candidates, unpublished or already-started activity) and names the prerequisite tool add_guest_candidates. That is explicit when-to-use and when-not-to-use guidance.

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