Create Email Letterhead

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

Annotations already convey that this is a write operation (readOnlyHint=false) and idempotent. The description adds domain context about the letterhead structure (colors) but does not disclose behaviors like duplicate handling or permissions. It also mentions 'footer colors' though no footerColor parameter exists, which is a minor inaccuracy.

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 organized in two paragraphs: purpose first, then parameters. The parameter list is somewhat redundant with the schema but remains compact and readable. No irrelevant information is included.

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 straightforward creation tool with full schema coverage and annotations, the description is sufficient. It explains the artifact and its purpose without needing to describe output details. Minor missing context about potential side effects is covered partly by the idempotency annotation.

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 100%, so the baseline is 3. The description adds value by clarifying the roles of backgroundColor vs bodyColor vs headerColor, which the schema's short descriptions only partially convey. However, much of the parameter list paraphrases the schema.

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 a specific action 'Creates a Letterhead' and identifies the resource. It further explains the letterhead's purpose as a visual wrapper for HTML email templates, clearly distinguishing it from sibling tools like email template creation.

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 when to use the tool by explaining that letterheads can be referenced by email templates for brand consistency. It does not explicitly name alternatives or state when not to use it, but the context is clear and useful for an AI agent.

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