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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false. Beyond that, the description adds real behavior: replies come back by email to the user's address (a response channel not in the schema) and attachments must be hosted links rather than uploads. It omits post-submit behavior such as ticket IDs or confirmation, which keeps it from a 5.

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?

Three short sentences, each carrying distinct information: purpose, response channel, attachment format. Front-loaded with the action and zero 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?

With no output schema, the description correctly explains how the user receives the answer (email) and the attachment constraint. For a create tool it is nearly complete; only the post-submission outcome (e.g. whether a ticket reference is returned) is left unstated.

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 only 33%: body is documented in the schema, subject is not. The description compensates for the attachments parameter ("links, e.g. a screenshot URL") but says nothing about what a good subject should contain, so the low-coverage gap is only partly closed.

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+resource ("Send a message to Caly support") and enumerates concrete intents (bugs, billing, restoring deleted items). The create-vs-list split with sibling list_support_tickets is implicit from the verb rather than explicitly named, so it stops just short of a 5.

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 parenthetical use cases ("bugs, billing questions, restoring something deleted") give an agent a clear trigger for selecting this tool. There are no exclusions or explicit alternatives, so it is context-rich but not a full when/when-not guide.

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