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

With no annotations, the description carries the full burden and does it well: it discloses the free/cost status, privacy behavior (companies named with IČO, private persons anonymous), the rate-limited live fallback for unknown VINs, and what data is absent (mileage, plate lookup). These are exactly the behavioral traits an agent needs before calling.

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 first sentence is front-loaded with the core action, registry name, and return contents; two short follow-ups cover limitations and fallback. It is dense but every clause (privacy rules, rate limiting, missing data) earns its place, with only minor compression possible.

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 one-parameter, no-annotation, no-output-schema tool, the description enumerates the returned data domains, privacy treatment, known data gaps, and the unknown-VIN fallback behavior. An agent can decide whether to call it and interpret the result without further context.

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 single VIN parameter already documents the 17-character, no-I/O/Q constraint. The description restates the 17-character format but adds no new syntax, normalization, or edge-case guidance beyond the schema, so 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?

The description states a specific verb (vehicle history check) and resource (official Czech vehicle registry), tied to a 17-character VIN. It lists the exact returned data domains (owner timeline, STK history, import origin, deregistration, seized flags, specs), so an agent can tell precisely what this tool produces versus the valuation/market siblings.

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?

It gives clear usage context: free lookup, unknown VINs fall back to a rate-limited live lookup, and it explicitly excludes mileage and license-plate lookups so the agent knows what not to attempt. It stops short of naming a sibling alternative for related needs (e.g. valuation), so it is clear but not fully routing.

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