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

Annotations already disclose that this is a non-readonly, non-destructive, non-idempotent, closed-world operation. The description adds useful context that the template can be sourced from an existing newsletter or a full document, but it does not mention permissions, duplicate-name behavior, return value, or what happens if the supplied campaignId is invalid.

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 no wasted text. It is appropriately compact, though the phrase 'or a full email document' is slightly terse and leaves the relationship between the two creation paths implicit.

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 create/mutation tool with no output schema, the description covers the two main input paths but leaves out what is returned, whether a new template ID is produced, and how naming or category selection affects the result. It is minimally adequate but not fully complete for invocation confidence.

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 40%, so the description should compensate. It clarifies the two core source parameters, campaignId and document, but does not explain the required name, the category enum, the description field, or the exclusivity between campaignId and document.

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: saving an existing newsletter or a full email document as a reusable template. It is clear what the tool does, but it does not explicitly distinguish itself from siblings like update_email_template, use_email_template, or create_saved_reply.

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 implies two creation paths (existing newsletter via campaignId or a full document), which gives some usage context. However, it does not state when to choose this tool over update_email_template, create_saved_reply, or create_newsletter, and it does not explain prerequisites or when each source should be used.

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