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

Beyond the annotations (non-read-only, non-idempotent, non-destructive) the description discloses the real consequences: the message is sent immediately, it is recorded in the place's AI log with an Undo window of one day, and it degrades to a sendable draft when mode is draft or an under-18 participant is in the thread. Those are meaningful side effects an agent cannot get from the annotations. It stops short of stating permission requirements or what is returned on success.

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 short and the identity/attribution point is front-loaded, so nothing is padded. But the middle sentences are compressed into fragments ('Only what they want said.', 'Run the place: sent now, in its AI log with Undo for a day.') that cost the reader more than the bytes saved.

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 mutating send tool with no output schema, the description covers the important behavioral branch (immediate send vs. draft) and the identity it posts under. It omits what a successful call returns (particularly for draft mode, where a card is created) and any permission or eligibility prerequisites for acting as the place.

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 50%, and the description does add meaning the schema lacks: it explains the real trigger for draft mode (mode=draft OR an under-18 participant in the thread), which the schema's 'as far as yourAi goes' does not make clear. It says nothing about replyTo, conversationId, or the 2400-character text limit, so the undocumented half of the schema is not compensated for.

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?

It names a concrete verb and resource ('Answer in a place's inbox AS THE PLACE') and the attribution model ('everyone sees its name with "via" your app, never the person's'), which separates it from reply_in_thread and pro_message. The telegraphic phrasing ('Run the place:', 'Only what they want said.') blunts an otherwise specific purpose statement.

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?

The 'AS THE PLACE' framing implies when to pick this over a personal reply, and the closing clause says when a draft is produced instead of a send. It never names an alternative tool or states an explicit 'use X instead when Y', so the agent must infer the routing from the sibling list.

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