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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful scope information (which fields are searched) but does not disclose other behavioral traits such as result ordering, matching semantics, or response structure beyond the schema defaults.

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 one concise sentence in German plus its English translation, with no filler. The key search behavior and scope are front-loaded before any schema details.

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 read-only search tool with 5 parameters, the description plus schema covers the search scope, required/optional parameters, and pagination. Because there is no output schema, a small gap remains around what the returned matches look like, but this is unlikely to block correct invocation.

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?

With schema coverage at 60%, the description becomes important for the undocumented 'query' parameter, and it delivers by specifying that the query applies to subject, recipient name, and letter content. It does not explain the 'reasoning' parameter, but the other three parameters already have schema descriptions, so the overall semantic gap is small.

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 ('Durchsucht' / 'searches') and resource ('Briefe des Partners' / 'partner's letters') and names the exact searchable fields: subject, recipient name, and letter content. This clearly differentiates the tool from sibling list/retrieval tools like letter_list and letter_get, which do not perform full-text content 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?

The description implies that this is the tool to use for full-text search over letter fields, but it does not explicitly state when to prefer it over alternatives such as letter_list or letter_get, nor does it give exclusions. No alternative tool is named, so the agent must infer the selection from the word 'Freitext'.

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