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

With no annotations at all, the description carries the full burden, and it does disclose the delivery path (owner dashboard, plus a notification channel only on paid plans) and that the owner replies to reply_to. That is genuinely useful side-effect context. It is silent on failure behavior, rate limits, and whether the sender's identity or IP is exposed, which matters for a send-style tool.

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 compact sentences, with the destination and delivery behavior front-loaded and the consent constraint last. No filler. A slightly tighter phrasing would earn a 5, but nothing here is wasteful.

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 three-parameter outbound message tool with no annotations and no output schema, the description covers recipient, delivery channel, and reply path, which is the core of what an agent needs. It still leaves the response side undefined (no confirmation, no message ID, no indication of what the tool returns), so the agent cannot predict the outcome of a call.

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 only 33%, so the description needs to compensate, and it does not. It restates what the schema already says about reply_to ("the owner replies to reply_to") and says nothing about the optional 'name' parameter, which is completely undocumented in both places, nor about the 2000-character limit's practical meaning.

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 gives a specific verb and resource ("Leave a message for Demo Bakery") and clarifies that it is an inquiry routed to the business owner rather than an order, which is enough to tell it apart from start_order. It stops short of naming a sibling or stating an explicit contrast, so it is clear but not maximally differentiated.

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?

"Only send with the user's consent" is a real precondition, so the description does more than imply usage. However, it gives no when-not guidance and never contrasts this with alternatives such as start_order or get_business_info, leaving the agent to infer when an inquiry is preferable to placing an order.

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