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

Annotations only indicate readOnlyHint and openWorldHint. The description adds valuable behavioral context: it is heuristic, noisy by design for common surnames, auto-skips persons with >50 matching companies, and produces a SURNAME_TOO_COMMON note. It does not describe output structure or failure modes, but these are secondary given the strong caveats disclosed.

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 moderately sized but every sentence earns its place: purpose, best-use case, exclusion, alternative, and noise warning are all packed in without redundancy. It is front-loaded with the primary function. Slightly long but justified by the caveats.

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?

Even without an output schema, the description clarifies the tool's scope, limitations, and alternatives, which is essential for correct invocation. It does not describe the return format, but the walk-through nature and the note behavior give enough context for an agent to expect a chain-like result. Missing explicit output details prevent a 5.

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 already provides 100% coverage with descriptions for both 'ico' and 'max_depth'. The description adds context about surname-based heuristics and rare surnames, but does not significantly enhance parameter understanding beyond the schema. Baseline 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 clearly states the tool performs a 'surname-based heuristic walk through statutory bodies of related Czech companies'. It specifies the exact resource and action, and distinguishes itself from a true UBO source and sibling tools by noting it is best for shell-company unwinding with rare surnames.

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?

Provides explicit guidance on when to use ('Best for shell-company unwinding in small s.r.o. with RARE surnames'), when not to use ('NOT a true UBO source'), and names the alternative ('use the ESM'). It also warns about common surnames and the auto-skip behavior, giving clear decision criteria.

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