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

Annotations already flag destructiveHint=true and openWorldHint=true, but the description adds the specific traits that matter: the reply reaches the customer, it cannot be unsent, repeated calls create additional replies, and the optional status moves the conversation afterward (mirroring 'Send and close'). This is exactly the extra context annotations cannot express.

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 sentences, each load-bearing: purpose and scope first, the internal-note alternative second, the irreversibility and status side effect third. No filler and the critical constraints are front-loaded.

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 mutation tool with no output schema, the description covers what the agent needs: who receives the message, that the action is irreversible, retry semantics, and the side effect on conversation status. Nothing material is missing.

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 100%, so the baseline is 3; the description exceeds it by explaining that `status` relocates the conversation after sending and by framing it against the familiar 'Send and close' behavior. It does not add anything for `snoozedUntil` or `conversationId` beyond what the schema already states.

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 (send a reply), the resource (a conversation), the acting identity (signed-in teammate), and the delivery channel (email, chat, helpdesk ticket). It also distinguishes itself from the nearest sibling, add_note, so an agent can separate the two 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?

It gives an explicit alternative with the condition that selects it: 'For something only teammates should see, use add_note.' It also states the consequence of repeat invocation ('calling it again sends another reply'), which tells the agent this is not a safe retry.

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