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

Annotations already mark this as a non-destructive, closed-world write, and the description adds genuinely new context: an authentication requirement ("Owners only (needs sign-in)"), the visible destination, and the 300-character cap. It stops short of saying whether the agent gets confirmation or what happens on rejection (e.g., auth failure, over-length), which is the only meaningful remaining gap.

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?

Three tight sentences ordered by importance: audience/auth, action and destination, then usage condition and limit. No filler, and the parenthetical breadcrumb is high-value navigation detail rather than noise.

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 single-string, no-output-schema tool this covers everything an agent needs: who can call it, where the note goes, how long it may be, when to prefer chat instead, and what to write. Nothing about return values is required given the absence of an output schema.

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%, but there is only one parameter and the description compensates by explaining what a good note contains ("a customer question you couldn't answer... and what you need from them"). The "Up to 300 characters" line merely restates maxLength, so the value added is content guidance rather than syntax.

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?

Uses a specific verb and resource ("Leave the owner a short note") and names the exact destination ("Latchbell inbox (Inbox › Notes & activity)"), so the agent knows both the action and where the artifact lands. It also implicitly separates itself from conversational messaging by insisting the note is for cases where nobody is chatting.

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?

Gives an explicit use condition ("Use it when nobody is chatting with you (a run started by an event)") and an explicit counter-condition with the alternative action ("when the owner is in the chat, tell them there instead"). It even suggests suitable content (an unanswered customer question plus what's needed), leaving little to inference.

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