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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the mutation and non-destructive nature are covered. The description adds that it targets existing Tango support tickets and provides example content, but it does not disclose additional behavioral traits such as whether the message is appended, whether staff are notified, or any rate limits.

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 a single, front-loaded sentence with the core action stated first and useful examples following the dash. There is no fluff or redundant restatement of the tool name.

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 simple two-parameter mutation with annotations covering safety, the description is largely complete: it states the target resource, the action, and realistic use cases. It does not mention how to discover the ticket_id (e.g., via list_support_requests) or what the response will be, but the absence is not critical given the tool's simplicity.

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 compensate. It does partially by mapping 'message' to body and 'one of your existing Tango support tickets' to ticket_id, and the examples clarify what kind of content body should contain. However, it does not explicitly define the ticket_id format or body constraints, though the schema already covers those.

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 opens with the specific action 'Add a message to one of your existing Tango support tickets,' clearly identifying the verb, resource, and scope. The examples ('answer a staff question', 'add the error output...', 'confirm the fix worked') clarify the purpose, though it does not explicitly differentiate itself from similar sibling tools like add_comment.

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 situational context: use this when responding to a staff question, providing requested error output, or confirming a fix. It does not explicitly state when not to use it or name alternatives like submit_support_request for creating a new ticket, so it stops short of a 5.

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