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

The annotations indicate readOnlyHint=false and destructiveHint=false, but the description adds important behavioral context: it declares an 'Effect: workspace-change' and instructs retrying with the same idempotency_key, which is critical for agents. It also mentions the required permission (email_templates:write), adding value beyond the annotations.

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 one sentence followed by three concise statements (effect, retry, permission, API link). Every sentence provides essential information without redundancy. It is front-loaded with the primary purpose and then critical operational details.

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?

The tool has a complex input schema with nested objects and an output schema, so the description does not need to explain return values. The description covers the effect, idempotency, and permissions, but it lacks details on error handling or rate limits that could be useful given the complexity. However, the API reference link and rich schema compensate, making it largely complete.

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 schema description coverage is 100% and includes detailed descriptions for body_document (size limit, personalization tokens, anti-handlebars warning) and starting_point_id (exclusive with body_document). The description of the overall tool does not add parameter details, but the schema itself is richly documented, so the baseline is 3; however, the description's mention of idempotency_key usage and the schema's constraints push it to 5.

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 creates a reusable email template scoped to the authenticated workspace, which distinguishes it from siblings like email_templates_update and email_templates_preview. The verb 'Creates' and resource 'email template' are specific and 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?

The description does not explicitly state when to use this tool versus alternatives, but it mentions the workspace scope and provides an API reference link. There is no guidance on when not to use it (e.g., when to use email_templates_update instead), so it is adequate but lacks exclusions.

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