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

Annotations already declare readOnlyHint=true and idempotentHint=true, lowering the bar. The description adds useful behavioral context: it returns all matching entries rather than one, and it states that both key-number fields of the entry are considered during matching. No behavioral claim contradicts the annotations.

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 short sentences with no filler; the main purpose is front-loaded and the second sentence adds a precise matching detail. Every clause earns its place.

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 simple read-only code lookup with a full input schema and an output schema, the description plus annotations cover what an agent needs to invoke it correctly. It clarifies the lookup semantics and does not need to restate return-value details because an output schema exists.

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 schema already covers both parameters at 100%, so the baseline is 3. The description adds extra meaning by specifying that the supplied code is matched against both key-number fields of the entry, which is not in the schema description for 'code'.

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 uses a specific verb ('Liefert') and a specific resource ('Einträge des Alphabetischen Verzeichnisses') tied to a lookup key ('bestimmten OPS-Kode'). It also clarifies the return scope ('sämtliche Bezeichnungen...'), which distinguishes this by-code lookup from the sibling *_search tools and from lookups in other code systems.

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 intended use is reasonably clear: call this when you have an OPS code and need all alphabetical index entries that reference it. However, the description does not explicitly state when not to use it or contrast it with opsalpha_search, so the guidance remains 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.