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

The description reveals deterministic ordering ('exact registration-number matches first'), normalization rules (Cyrillic/Latin, separator-insensitive numbers), and a per-result web_url field—none of which appear in annotations. It aligns with readOnlyHint/idempotentHint and adds genuinely useful behavior 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?

Three sentences, each with a distinct role: purpose/scope, ordering, normalization + output shape. No filler; the most decision-relevant information is front-loaded.

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 an 8-parameter optional-query tool with a rich output schema, the description covers search semantics, ordering, normalization, and output URL without duplicating the schema. Pagination and defaults are already in the input schema, so nothing critical 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?

Schema already documents all 8 parameters (100% coverage), so baseline is 3. The description goes beyond by defining q normalization equivalence (УПС-0129 ≡ УПС 0129 ≡ UPS-0129) and 'partial match' filtering intent, which helps the agent use q and filters correctly.

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?

Description opens with a specific verb ('Search'), names the exact resources ('Ukrainian State Ship Registry and Ship Book'), and states the mechanism ('free-text query and structured filters'). This differentiates it from sibling lookup_vessel by emphasizing free-text search rather than a single exact identifier.

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 the search use case but never tells the agent when to prefer this tool over lookup_vessel or get_registry_stats. It names no alternatives, no exclusions, and no prerequisites, so an agent must infer routing from the tool name and sibling list.

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