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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety and idempotency profile is covered. The description adds the important behavioral constraint that the message wording must be customer-approved and verbatim, but says nothing about permission requirements, what happens on a duplicate clientMessageId, or the result of a successful call.

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?

A single front-loaded sentence with no filler; the verb and resource lead. It is efficient, though the terseness is a symptom of under-specification rather than deliberate economy.

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 six-parameter mutation with zero schema descriptions and no output schema, this is far too thin. The agent gets no information about required fields, idempotency semantics via clientMessageId, the meaning of the forced confirmed=true flag, or expected results.

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% across six parameters, so the description carries the full explanatory burden and falls short. It only hints at the body ('exact customer-approved message') and obliquely at confirmed, leaving orderId, subject, attachmentIds, and the idempotency role of clientMessageId completely 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 ('Create a support conversation') and adds the distinguishing constraint that the body must be the exact customer-approved message. It does not explicitly name siblings such as support_message_send or support_conversation_close, so an agent must infer the boundary between creating a conversation and appending to one.

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?

'Using the exact customer-approved message' implies a precondition and a workflow (message must already be approved by the customer before calling), which is useful implied guidance. However, no alternative is named and no explicit when-not condition is given, so the agent must infer that support_message_send is for existing conversations.

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