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

No annotations are provided, so the description carries the full burden. It discloses the multi-source lookup behavior (primary official list, fallback to QRZ.com/HamQTH), which is valuable. However, it doesn't describe what happens when a callsign is not found, response format, or any access limitations. The fallback disclosure adds some context, but the description is still minimal.

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 description is two sentences long, front-loaded with the action and resource, with no redundant wording. The second sentence adds relevant information about data sources. Every word 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 lookup tool with well-documented parameters, the description is complete enough. It states the purpose, output, and data sources. However, the lack of an output schema and no mention of not-found behavior means the agent doesn't know the exact response structure. Given the tool's simplicity, this is a minor gap, so a 4 is reasonable.

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 input schema covers both parameters (callsign, include_address) with clear descriptions. The tool description itself does not add parameter-level details beyond what the schema already provides. With 100% schema description coverage, the baseline of 3 is appropriate.

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 ('Sucht') and resource ('österreichisches Amateurfunkrufzeichen') and clearly states the outcome ('gibt Inhaberinformationen zurück'). It distinguishes itself from sibling tools like callsign_validate (format validation) or callsign_available (availability) by focusing on owner lookup.

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 clearly implies the tool is for looking up Austrian amateur radio callsigns and retrieving owner information. It provides context about data sources (official list with fallback to QRZ.com and HamQTH) but does not explicitly name alternatives or state when not to use it. Since the context is clear, a 4 is appropriate.

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