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

Annotations already mark the tool read-only and non-destructive; the description adds useful behavior beyond that: the list grows with approved templates, the default result is text-only, and presetId triggers a real-composer preview. No contradiction with 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 key information is front-loaded and the structure is logical, but the German and English sections duplicate the same content and add some non-essential framing like 'grows with every curated design.' It is organized yet longer than necessary.

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?

There is no output schema and no clarification of what fields the list returns, nor how pages and resolution affect the preview. For a tool with four optional parameters and no output schema, the description leaves too many operational details unspecified.

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 only 25%, and the description compensates only for presetId. The meaning and effect of pages, resolution, and reasoning are left entirely undocumented, so an agent cannot know how to set them correctly.

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—'Returns the owner-approved native-v2 letterheads'—and clarifies the resource as curated, safe starting points for common letter types. It is clear, but it does not explicitly differentiate from sibling letter_design_list or letterhead_list, so it stops short of a 5.

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 gives a clear conditional: use the plain list for cheap text-only results, or pass presetId to render exactly one composer preview with an inline PNG. It does not name alternatives or say when not to use this tool, so it lacks explicit exclusions.

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