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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantive behavioral context beyond them: the verdict enumeration, the as_of date, and the critical caveat that most companies are 'unknown' and that 'unknown' does not mean alive. That data-quality warning materially changes how an agent should interpret and report results.

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?

Front-loaded with the operation and its key caveat, and every clause is relevant. The 25-company limit is stated twice (opening and closing sentence), which is mild redundancy, and the example questions add length but earn their place as disambiguation.

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?

With no output schema, the description still tells the agent what comes back per company (verdict, as_of, explanation) and warns about the dominant 'unknown' case. Combined with annotations covering the safety profile, an agent has everything needed to call and interpret it correctly.

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 coverage is 100% and the schema itself documents the company_number_norm format, court-code derivation rule, and maxItems. The description only restates the 25-company cap ('up to 25', 'Max 25 companies per call'), adding little syntax or meaning beyond the schema; baseline 3 applies.

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 specific verb (checks), a specific resource (up to 25 German companies), and the exact output vocabulary (alive / dead / unknown, with as_of and explanation). This is clearly separable from siblings like get_company_profile, which the description explicitly routes to for full profiles.

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?

Gives explicit when-to-use scenarios (cleaning CRM data, reviewing a supplier list) plus concrete example user questions, and names the alternative tool for a deeper per-company need. The boundary between this batch-status tool and get_company_profile is unambiguous.

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