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

With readOnlyHint=true already covering the safety profile, the description adds valuable context beyond the annotation: the return shape (groups[] with id/hash/hubUrl/slugs/urls) and the cross-tool behavioral contract where an unknown slug produces ok=false unknown_auswahl in get_auswahl_item. It does not describe pagination or ordering, but those are minor for a hub listing.

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 WHAT/RETURNS/USE format is front-loaded and zero-waste: the core purpose comes first, followed by the return contract and the usage routing. Every clause earns its place, and the structure makes scanning trivial for an agent.

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 low-complexity tool (one optional param, readOnly annotation, output schema present), the description is complete: it states what it does, what it returns, when to use it, and the downstream failure mode. Nothing an agent needs to invoke it correctly is missing.

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%, and the locale parameter's schema description is exceptionally detailed (defaults, URL prefix behavior, what it does not change, maps-locale exclusion). The tool description adds nothing about locale, so the baseline 3 applies — the schema does the heavy lifting, which is acceptable.

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 states a specific verb (list) and resource ('Auswahl hub groups'), anchors it to a concrete endpoint (/auswahl), and differentiates it from the sibling get_auswahl_item by framing this as the slug-discovery counterpart. An agent can tell exactly what this tool does without opening the 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?

The description gives an explicit use case ('USE to discover valid slugs for get_auswahl_item') and names the sibling it feeds into, plus the downstream failure contract for unknown slugs. It lacks explicit when-not-to-use exclusions versus other listing/search siblings, but the primary routing logic is unambiguous.

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