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

Annotations already declare the write/open-world/non-destructive profile, but the description adds substantial context beyond them: text-only chat, read-only after guest checkout, a per-call confirmation default that can be switched off, and the requirement for a Cotlet API key with app access. The 'reaches other people' warning is a meaningful external-side-effect disclosure.

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?

The opening two sentences restate the same action ('Reply to a guest in Property Chat' and 'Sends a text message to a guest in Property Chat'), and the confirmation guidance is spread across two sentences. Front-loaded and readable but with noticeable redundancy.

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 write tool with no output schema, the description covers the action, both input modes, side effects, confirmation flow, and auth needs — enough to call it correctly. It omits any note on return/acknowledgement shape, but that is minor 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 100%, so the baseline is 3, but the description adds the semantic distinction between the mutually exclusive chat_id (reply) and booking_ref (start new from booking) modes plus the availability condition for booking_ref. This meaningfully supplements the terse schema descriptions.

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 states a specific verb+resource (send/reply in Property Chat) and distinguishes two operating modes: replying via chat_id and starting a chat from a booking via booking_ref. An agent can tell this apart from the read-only chat siblings (get_chat, list_chats) without opening a 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 explicit conditional guidance on which parameter selects which mode (chat_id to reply, booking_ref to start from a booking when the Chat option is shown) and states the 'read-only after checkout' constraint. It stops short of naming sibling alternatives like list_chats or get_chat, so it's clear context without full routing.

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