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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: it discloses that the tool compares a supplied rate against the 25-%-Grenze and reports the change versus 2024, which is the actual logic an agent needs to trust the result.

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?

It is dense but front-loaded: the lookup scope comes first, the optional check second. The German and English sentences partially duplicate each other, but the bilingual phrasing serves retrieval, and no sentence is pure filler.

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 a full output schema, the description need not explain return values, and it does cover the eligible Nr. categories, measure type, and the optional rate-check path. Only the fallback behavior when neither kostensatz nor gesamtkosten is supplied is left implicit.

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 100%, so the enum meanings for 'art' and 'ziel' and the numeric bounds are already fully documented in the schema. The description only restates which fields exist and that 'teilnehmende' is group-only, adding no syntax or edge-case meaning beyond the schema — 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 (B-DKS 2026 Bundesdurchschnittskostensatz per Maßnahmestunde) and a specific action (lookup plus rate check), and scopes it to § 45 SGB III Nr. 1/4/5 and Einzel-/Gruppenmaßnahme. None of the siblings (avgs_fristen, ba_formulare, glossar) overlap with cost-rate lookup, so the agent can route unambiguously.

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 signals the conditional branch — the lookup is the default, and 'Optional: eigenen Kostensatz oder Gesamtkosten + Stunden (+ Teilnehmende) prüfen' tells the agent when to supply the optional parameters. However, it never states when NOT to use this tool or which sibling to reach for a deadline/form/term question, so usage is implied rather than explicit.

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