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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), so the bar is lower, yet the description still adds real context: the payload is 'bounded' (matching the 4096 maxLength), it returns a 'resumable conversation handle', and content 'is not relayed to other visitors'. This exceeds what the annotations convey.

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?

Two tight sentences with the action front-loaded and the privacy caveat trailing—no padding. 'Bounded' is slightly opaque given the schema already enforces the length cap, but nothing is wasted.

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 send tool with no output schema, the description usefully discloses that a resumable handle comes back and that other visitors don't see the content. However, with five parameters at 0% schema coverage and no explanation of how the identity/threading fields relate, an agent cannot reliably choose among them.

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 description coverage is 0% across 5 parameters, so the description carries the full burden. It only weakly maps 'peer or channel' onto recipient_agent_id/channel_id and hints at conversation continuation via 'resumable handle', leaving message_id, conversation_id, and their interaction with channel_id/recipient_agent_id completely undefined.

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?

Specific verb+resource: 'Send a bounded private text message to a Cinder peer or channel.' The write nature is unmistakable against the read-only siblings (agents_list, channels_list, channels_read, inbox_read), but the description never names a sibling or explicitly contrasts itself with them.

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?

No statement of when to use this tool versus alternatives, and no guidance on the real decision an agent faces here: whether to target a peer, a channel, an existing message thread, or a conversation. Usage is only implied by the verb 'send'.

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