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

Annotations already indicate readOnlyHint and non-destructive behavior. The description adds one useful behavioral detail—the preview URL is only valid for 24 hours—which is beyond the schema. However, it does not describe return shape, pagination, or other response behavior, so it provides only modest extra transparency.

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 short, front-loaded with the primary action, and includes the key detail about URL validity. The bilingual repetition is intentional and not filler for a German/English tool surface.

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 simple read-only list tool with no required parameters and no output schema, the description gives enough to understand what is returned: letterheads with preview URLs. It could mention whether the list is complete or how the optional reasoning parameter is used, but those are minor gaps given the low complexity.

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 0%, and the description does not explain the only parameter, 'reasoning'. Since the parameter is optional and named in a self-explanatory way, the impact is limited, but the description still does not compensate for the lack of schema documentation.

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 a specific verb and resource: it states it lists the letterheads stored in the partner profile. It also mentions the distinguishing detail of a short-lived preview URL, which separates it from related letter/design list tools.

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 context is clear: use this tool to retrieve letterheads already saved in the partner profile, with preview URLs. It does not explicitly name alternatives or exclusions, but the scope is obvious enough from the description and the sibling-tool names.

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