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

Adds real behavior beyond the annotations: the payload is a PDF email and the call 'waits for the owner's approval', which signals an approval gate not captured by destructiveHint/openWorldHint. It does not clarify whether the call blocks, what a rejection returns, or whether re-sending is possible.

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, front-loaded with the action and followed by the key operational caveat. No filler.

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 5-param mutation tool with full annotations and no output schema, the safety and workflow essentials are covered. The one meaningful gap is the ambiguity of 'waits for approval' — whether the call blocks, times out, or returns a pending state.

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?

Coverage is 80%, so the schema already documents `to`, `message`, `subject`, and `change_order_id`. The description only restates the `to` default already present in the schema and adds nothing about `copy_me` or subject/message interplay; baseline 3 applies.

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?

Concrete verb+resource ('Emails the change order as a PDF') with the recipient scope stated. It is implicitly distinguished from send_estimate/send_invoice by the resource name, but the description never names those siblings to prevent confusion.

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?

The recipient default ('the customer or the addresses you give') implies when to pass `to`, but there is no explicit statement of when to use this versus send_estimate/send_invoice, nor prerequisites such as the change order needing to be in a sendable state.

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