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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description does add real value beyond that by promising each new value alongside the previous one, the source, and explicitly flagging values that are not yet officially published – a meaningful data-quality caveat. That is a genuine addition, but it stops short of describing ordering, empty-result behavior, or coverage granularity.

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?

Two sentences, well front-loaded with the hard scope constraint ("Germany only") before the purpose, followed by a concrete example and the return shape. The example list is slightly dense but every clause contributes information.

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 an output schema present, return values need not be explained, yet the description still sketches them (new value, previous value, source, provisional flags). Parameters are fully specified in the schema and the safety profile is fully covered by annotations, leaving nothing an agent needs in order to call this correctly.

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?

Both parameters are fully documented in the schema (100% coverage), including their defaults (von defaults to today, bis to one year later). The description only restates the "between two dates" framing without adding format or edge-case detail, so the schema carries the load and baseline 3 applies.

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 names a specific resource (a calendar of Rechtsänderungen in German employment-law values) and a specific operation (comparing values between two dates), plus what each entry contains. An agent can distinguish it from lookup-oriented siblings such as rechtswert or rechtswerte_suchen by the temporal-diff framing, though no sibling is named explicitly.

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?

Usage is implied by the concrete example ("what changes on 1 January: minimum wage, mini-job limit, contribution ceilings and rates") and by the "Germany only" scope restriction. However, there is no explicit when-to-use/when-not guidance and no pointer to the alternative siblings that retrieve a single current value rather than a change calendar.

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