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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds substantive context beyond them: which statutory reductions are applied, the 1182/71 next-working-day rollover, an explicit rules-as-of date (2026-07-14), and that each computational step is explained. It stops short of saying what the response payload actually contains, so it is strong but not exhaustive.

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 core purpose and legal basis are front-loaded in the first two sentences, with scope limits and the sibling pointer following. The five example questions are valuable for retrieval but add length; the parenthetical rule-version note is dense yet justified.

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 that a step-by-step explanation is returned and pins the legal snapshot date, which is important for a rules-driven calculator. Six parameters are fully documented in the schema, and the description supplies the jurisdictional and procedural boundaries an agent needs before calling it.

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, but the description adds legal meaning by grouping elektronisch, vorinformation and dringlichkeit as the reduction factors that shorten or set the minimum period, and by framing the tool's scope around framework/procedure combinations. Those links are inferable from the schema but the description makes the interaction explicit.

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 verb (calculates) and a precisely scoped resource (the end date of a submission/participation deadline in an EU procurement procedure), then narrows it to VgV and VOB/A section 2 EU. It explicitly notes that the § 134 GWB standstill period belongs to calculate_standstill_period, so an agent can separate it from that sibling without opening either schema.

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?

Names the triggering request types ('by which date bids are due', 'whether the minimum period can be shortened') and backs them with five concrete example user questions. It also states the exclusion explicitly by routing standstill-period questions to calculate_standstill_period, leaving little to inference.

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