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

Well beyond the readOnly/idempotent/non-destructive annotations, it discloses partial results (omittedForSize), missing-data semantics (absent vatRegistration, ANALYSED not implying complete pipeline), ordering guarantees, duplicate-UID collapsing, and malformed check-digit rejection. These tell the agent exactly how to interpret a short or partial answer.

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?

Purpose and limits are front-loaded in the first clause, and every subsequent sentence carries distinct operational information rather than filler. It is dense and a couple of sentences chain multiple facts with em-dashes, which costs some readability.

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?

An output schema exists so return shape need not be restated, yet the description still covers the non-obvious response keys (notInDataset, omittedForSize) and the guarantees around them. Nothing an agent needs to call this correctly or interpret its output 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 coverage is 100% and the schema already documents 'formatted or plain; at most 25 per call', so the baseline is 3. The description still adds meaning about the parameter's behavior: answer order mirrors request order, duplicates collapse to one, and invalid UIDs are rejected rather than silently dropped.

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 first clause states a specific verb and resource with scope: 'Full detail for one or several companies (1 to 25) by UID'. It positions itself against siblings by calling itself 'the second half of a search' and by naming load_company for the one-at-a-time case, so an agent can distinguish it without opening any schema.

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 clearly frames the tool as the batch follow-up to a search and names load_company as the single-record alternative, with notInDataset reasons pointing there. It stops short of an explicit 'use this when / do not use this when' statement, so usage is strongly implied rather than spelled out.

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