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

Adds meaningful behavior beyond the annotations: the message is emailed to the host, replies surface in get_messages, and the tool is only available in a defined window after checkout. Annotations already declare the write/non-destructive/open-world profile, so this description usefully fills in side effects and follow-up location.

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?

Four short sentences, front-loaded with the core purpose, and the examples and window constraint each add real information. No wasted filler, though the sentences are not maximally compressed.

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?

No output schema exists, so the description appropriately explains that replies appear in get_messages and states the availability window. But for a three-parameter write tool it omits essential argument semantics (booking_id, guest_email), leaving the agent to guess.

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%, so the description must carry parameter meaning, and it does not. It never explains booking_id or guest_email, and only loosely implies that body should contain the guest's own wording. Two of three parameters are wholly undocumented.

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?

States a specific verb and resource ('Send a message to the host on the guest's behalf') and gives concrete examples of the kind of content. However, it never distinguishes itself from the sibling tool ask_host, leaving ambiguity about which messaging tool applies.

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 clear usage context (questions about check-in, late arrival) and a hard temporal constraint ('Open from the request until two weeks after check-out') plus the constraint 'Only send what the guest asked you to say.' It stops short of naming an alternative or exclusion such as ask_host, so it is clear context without routing guidance.

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