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

Annotations already cover safety (read-only, idempotent, closed-world), so the description's added value is the domain behavior: the 28 June 2025 applicability date, the <10 employees / EUR 2m thresholds, the 2016/2102 overlap for public bodies, and the instruction to ask rather than guess. The 'informational, not legal advice' disclaimer is also useful framing. Slight gap: it doesn't hint at what the verdict/sources output contains, though an output schema exists.

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-loads the trigger condition and the legal instrument before any detail, and every clause carries content (date, thresholds, per-service rule, no-guessing rule, disclaimer). Dense but not padded; the parenthetical French title is slight surplus for most agents.

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?

Output schema exists so return values needn't be described, and the description supplies everything else an agent needs to invoke correctly: trigger, granularity (one call per service), input-gathering behavior, effective date, and the informational-advice boundary.

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%, so the baseline is 3. The description earns the uplift by restating the operative thresholds (fewer than 10 employees, turnover or balance sheet not above EUR 2 million) that drive the exemption logic and by naming the two parameter families that matter – headcount/financials and public-body status – which the schema documents individually but not as a decision rule.

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 precise check – whether the EAA (Directive (EU) 2019/882) applies – and names the exact decision factors: covered consumer services, the microenterprise exemption, and public bodies. An agent can tell immediately this is a scoped legal-applicability determination, not a general search or page scan.

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?

Explicitly says when to use it (user asks about applicability to their business/website), gives concrete examples (online shop, bank, transport operator), instructs one call per service for multi-service businesses, and explicitly prefers itself over a web search. That covers when, how many times, and versus the obvious alternative.

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