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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds behavior the annotations cannot express: a human-in-the-loop rule and an anti-spam constraint against auto-initiating communications, which is genuinely valuable context beyond the structured fields.

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 dense sentences that front-load the content before the usage directive, with no filler. Embedding a literal phone number is slightly unusual but serves as an example of the returned data without bloating the text.

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 zero-parameter, read-only tool with no output schema, the description conveys what is returned (contact fields) and the governing usage rule. It does not detail response format, but nothing essential for correct invocation 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?

The tool takes zero parameters, so the schema baseline of 4 applies; there is no parameter semantics to clarify. The description instead usefully enumerates the shape of the returned data (mobile, landline, WhatsApp, email).

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?

States a concrete verb+resource: retrieves live contact data from the imprint/contact page, and enumerates the returned fields (mobile, landline, WhatsApp link, email). It is distinguishable from siblings like get_flyer and get_listing, though it does not explicitly name them.

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?

Explicitly states when to use it ('nur dem Menschen zum Tippen zeigen nach klarem Kontaktwunsch') and when not to (agents must not initiate calls, WhatsApp or email). The condition and the prohibition are both spelled out, leaving nothing to inference.

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