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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation profile is covered. The description adds genuinely new behavioral context beyond the annotations: placeholder substitution rules ('a placeholder nobody supplies is replaced with nothing') and the fact that creation does not send. It does not cover what is returned (template id?) or duplicate-name 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?

Three tight sentences, front-loaded with the purpose and the required category values before the placeholder rules. The enumeration of category values is slightly redundant against the schema enum but reads as a quick reference rather than padding.

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 5-parameter mutation tool with no output schema and 20% schema coverage, the definition leaves gaps: no mention of the return value (presumably a template id needed for later update/send), no uniqueness or duplicate-handling guidance for 'name', and no note on required vs optional fields.

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 20%, so the description must carry more weight. It explains the placeholder convention for subject/body, which is real added meaning, but the category list merely restates the enum already in the schema, and the 'name' parameter is never explained (uniqueness, identifier usage).

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?

Opens with a specific verb+resource: 'Create a transactional template.' The verb distinguishes it naturally from update_template and list_templates in the sibling set, though it never names those siblings explicitly. Purpose is unambiguous.

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?

Adds a useful scope boundary — 'It creates the template only — sending needs a person' — which tells the agent creation does not trigger delivery. However, it never states when to create vs. reuse/update an existing template, nor does it name list_templates as a prerequisite check.

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