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

With no annotations provided, the description carries full burden for behavioral disclosure. It only restates the action ('send an email using a predefined template') without detailing side effects, requirements, rate limits, or that this actually sends emails (non-reversible). No additional behavioral context is given beyond the tool name.

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, focused sentence that is front-loaded and contains no wasted words. It efficiently conveys the core purpose without redundancy or extraneous detail.

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?

Although the schema is rich and covers parameters well, the tool is complex (6 params, nested objects, enums) and is a sending operation with potential side effects. The description provides no information about return values, safety, or when to use this tool among many email-related siblings, making it incomplete for confident invocation based on description alone.

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 100%, with each parameter already well-documented (e.g., bulk_mode explains options, provider lists examples). The tool description adds no extra parameter context, so the baseline score of 3 applies: the schema does the heavy lifting.

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 'Send an email using a predefined template', which clearly identifies the verb (send), resource (email), and scope (using a template). This distinguishes it from the sibling 'send_email' tool by emphasizing the template-based nature, even though it does not explicitly name the alternative.

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 usage for cases where a predefined template exists, but it does not provide explicit guidance on when to choose this over 'send_email' or other email tools, nor does it mention any exclusions or prerequisites. The usage context is merely implicit.

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