Validate Template

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

The description adds 'Persists nothing (safe to run)', which goes beyond the annotations by explicitly stating side-effect-free behavior. The readOnlyHint and idempotentHint are present, and the description reinforces them without contradiction. This adds useful context about safety, though it does not elaborate on rate limits or exact behavior during rendering.

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 two sentences with no fluff. It front-loads the core purpose, then provides the safety guarantee and a necessary input requirement. Every sentence earns its place.

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 tool with 7 parameters and an output schema, the description covers purpose, safety, and the main input constraint. It does not explain the meaning of layout_template or template_type, but the output schema likely defines return structure. Given the sibling context and annotations, it is reasonably complete, though not exhaustive.

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 coverage is only 14%, so the description carries the burden for parameter meaning. It adds a key constraint: at least one of subject, html_body, or text_body must be provided, which is not encoded in the schema. However, other parameters like template_type, layout_template, and inline_css_for_html_test_render remain unexplained, leaving gaps in semantic understanding.

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 clearly states the tool's function: 'Validate and render-preview template content.' This specific verb+resource combination distinguishes it from sibling tools like create/edit/delete template or send_email. The preview aspect makes it stand out from simple get_template.

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 pre-send validation but does not explicitly state when to use this tool vs alternatives. It provides a parameter requirement ('Provide at least one of subject, html_body, or text_body') and a safety note, but no direct comparison to other tools. This is implied usage rather than explicit guidance.

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