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

Annotations already flag destructive behavior, but the description adds meaningful context beyond that: the vendor sees the message in their Servana inbox, and the action contacts a real business requiring the user's explicit approval. This explains the real-world consequence and approval prerequisite without contradicting the annotations.

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 description is compact and front-loaded with purpose, followed by user-required content guidance and the approval warning. Every sentence earns its place, and there is no redundant 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 two-parameter messaging tool, the description covers the purpose, expected message content, vendor-side visibility, and the approval requirement. It is complete enough for an agent to invoke correctly, though it does not address post-send outcomes or error scenarios, which is a minor gap given the simple scope.

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 100%, so both vendor_slug and message are already documented structurally. The description reinforces that the message should include the user's needs and contact details, but it does not add new parameter information beyond the schema.

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 and resource: sending a message or booking enquiry to a Servana vendor on the user's behalf. It clearly distinguishes this from the sibling tools like search_vendors and estimate_service_request by focusing on direct vendor messaging and the user-approval requirement.

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 description gives clear context for when to use the tool: when the user wants to contact a vendor with an enquiry. However, it does not explicitly contrast this with estimate_service_request or state when not to use this tool, so the usage guidance is implied rather than explicitly differentiated.

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