create_template

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

Annotations already convey write operation (readOnlyHint false) and non-idempotency. The description adds useful behavior about variable substitution at send time and previewability via render_template. However, it does not disclose what happens on duplicate template names or whether the template is immediately available, leaving some behavioral gaps.

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 extremely concise, two sentences, and front-loads the core purpose. Every sentence adds value, with no fluff or repetition of schema information.

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?

Given no output schema and 6 parameters, the description covers the essential purpose and a key behavior (variable substitution). It also references render_template for preview, tying it to the tool ecosystem. Lacking any mention of return values or error cases is a minor gap for a creation tool.

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?

The input schema has 100% parameter coverage with descriptions for all six parameters. The description reinforces the {{variable}} syntax but does not add new per-parameter meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

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 uses the specific verb 'Create' and identifies the resource as 'a reusable email template.' It also distinguishes from siblings by noting variable substitution and pointing to render_template for preview, clearly separating creation from listing or rendering.

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?

It instructs to use {{variable}} placeholders for personalization and notes they are substituted at send time, providing context for when to use this tool. It mentions render_template as a preview alternative, but does not explicitly exclude other tools like create_campaign or list_templates.

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