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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds genuinely non-obvious business logic: the 14:00 Berlin business-day cutoff that determines production start, which materially affects the answer an agent receives. It doesn't state determinism or response shape, but the cutoff rule is real added context.

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?

A single dense sentence that front-loads the purpose and then nests the qualifying scope and the cutoff rule. Compact with no filler, though the parenthetical stacking is slightly cramped.

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?

With no output schema, the description still indicates what comes back ('earliest and latest delivery date') and for a zero-parameter tool that is close to sufficient. It omits any note on whether the estimate is cached or how time zones other than Berlin are handled.

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 tool takes zero parameters, so the baseline is 4. The description usefully explains why no inputs are needed by fixing the context (placed now, Germany, DHL), which is the closest thing to parameter semantics available.

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?

States a specific resource ('expected delivery window') with an explicit scope qualifier ('for an order placed now (Germany, DHL)'). It clearly tells the agent this is a forward-looking shipping estimate rather than a price or care query, though it doesn't explicitly name an alternative sibling to differentiate against.

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 phrase 'for an order placed now' implies the usage context (answering delivery-time questions), and the Germany/DHL parenthetical scopes applicability. However, there is no explicit when-to-use vs. when-not guidance and no mention of alternatives such as calculate_price for cost questions.

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