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

With no annotations, the description carries the full behavioral burden and largely fails to: it does not state what happens with an invalid or unknown register number, whether an entry can be missing, what permissions are needed, or what the returned entry contains. It only discloses, via 'One entry', that the result is a single object rather than a list.

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?

A single, well-formed sentence with the resource and the key identifier front-loaded and no filler. Nothing needs to be trimmed and the critical information comes first.

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 single-parameter lookup with no output schema, the description covers the essential contract (what is returned and what key is needed), but leaves gaps around error behavior for bad register numbers and what fields the entry exposes. Adequate but not complete.

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 0%, so the description must compensate, and it partially does by identifying the parameter as a register number and giving a concrete format example ('e.g. R001234'). It adds no information about validation rules, case sensitivity, or whether the 'R' prefix is required.

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 verb ('get'), a specific resource ('lobby register entry'), and scopes it to the German lobby register, so the agent knows exactly what is retrieved. It does not explicitly differentiate itself from the sibling search_lobby_register, but the singular 'one entry ... by register number' implicitly distinguishes it from a search.

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 only implied: the example register number ('e.g. R001234') signals that the caller must already hold a valid register number, which in turn implies search_lobby_register should be used first when the number is unknown. No when-to-use or when-not-to-use guidance is stated, and no alternative is named.

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