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

Beyond readOnlyHint/openWorldHint, it discloses provenance ('every fact has a source URL'), data quality ('unconfirmed facts are marked verified=false'), cost ('free'), and a hard boundary ('Mandate never files or signs for anyone'). Those are exactly the behavioral facts an agent cannot infer from annotations.

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-loaded with the core value ('How to form a limited company... in one call') followed by a dense but purposeful enumeration of returned fields and two short constraint sentences. Every clause carries information, though the parenthetical lists make it heavier than ideal.

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?

No output schema exists, and the description fully compensates by listing the returned data points including the verified flag and source URLs. Together with the explicit non-filing disclaimer, an agent has everything needed to decide to call and to interpret results.

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 adds value by enumerating the concrete legal forms (GmbH, SARL/SAS, SRL, BV, sp. z o.o., OÜ) and per-country facts, which clarifies what the legal_form filter matches and what a country query returns.

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 specific resource ('limited company formation in any of the 27 EU states') and enumerates exactly what data comes back: main forms, minimum share capital, notary requirement, online formation, portal URL, register, steps, languages, non-resident ID rules. This makes it clearly distinct from siblings like get_company and get_post_formation.

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?

Gives clear usage context ('in one call', omit country for an all-27 overview, optional legal_form filter) and sets expectations about scope (information only, never files or signs). It stops short of explicitly naming which sibling to use instead for company-specific or post-formation questions.

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