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

Annotations already disclose readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds essentially nothing behavioral: it does not say what is created or returned, whether the new template starts as a draft, or how request_id/idempotency_key affect behavior.

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 short sentences, front-loaded with the core action and the primary parameter hint. No wasted words, though the lowercase fragment opener and the incomplete coverage keep it from being exemplary.

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 3-parameter creation tool with no output schema and no schema descriptions, the definition is too thin. It omits the return shape, the template lifecycle state on creation, and two of three parameters, leaving real gaps an agent would need filled.

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 carry the load. It partially explains email_type (built-in type vs custom template key), which is genuinely useful, but leaves request_id and idempotency_key entirely undescribed, and does not explain the email_type pattern constraint.

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 verb 'create' is present, but the resource is described as 'an email' while the tool name and title point at an email *template* ('Create a custom email'). This mismatch means an agent cannot cleanly distinguish it from other create operations, and it does not differentiate from siblings like duplicate or publish. Purpose is inferable but vague.

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 only guidance is about parameter usage ('Use email_type for a built-in type or custom template key'). There is no when-to-use-this-vs-alternatives guidance despite many related siblings (duplicate, preview, publish, validate), and no prerequisites or when-not-to-use statement.

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