eu_check_applicability

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

Annotations already declare `readOnlyHint=true`, `destructiveHint=false`, `idempotentHint=true`, indicating safe, non-destructive, repeatable behavior. The description adds value by clarifying that results include confidence levels and article bases, emphasizes the non-binding expert nature, and documents specific error types. This contextualizes the tool's output and limitations beyond what annotations provide.

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 concise (three sentences) and well-structured: first sentence states purpose and scope, second describes output, third adds caveat and errors. Each sentence is necessary and provides distinct information with no redundancy. The Polish language is appropriate for the tool's likely audience.

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?

Given the tool's simplicity (2 parameters, no output schema, rich annotations), the description covers all essential aspects: what it does, what it returns, its non-binding nature, and error cases. The output description ('rules, confidence level, article basis') is sufficient without an explicit output schema. The tool's role among siblings is clear from the purpose.

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 50% (sector is well-defined with enum, subsector has a brief description). The description adds meaning by mentioning '6 EU regulations' as the context for sector selection, and by stating the output includes applicability rules and confidence. It also notes errors. This enriches understanding beyond the schema alone, though it does not detail parameter formats or constraints.

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 specifies the tool's purpose: checking which of 6 EU regulations apply to a given sector and optional subsector. It details output (applicability rules with confidence level and article basis) and distinguishes it from sibling tools (eu_article, eu_compare, eu_evidence, eu_search) by focusing on regulation applicability rather than article details, comparisons, evidence, or general 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 provides partial guidance: it states the tool returns an expert hint, not a binding legal assessment, and lists possible errors (`missing_arg`, `corpus_error`). However, it does not explicitly instruct when to use this tool versus its siblings (e.g., when to prefer `eu_article` or `eu_search`). The usage context is implied but not sharply defined.

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