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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description goes further by disclosing that results come from the service's own record of files read, that NTA retains files only 40 business days, and that the free window is the last 30 days. It also names the returned fields (file date, observed_at, event type, published dates), though the output schema already carries that. The 40-day/30-day limits are the genuinely additive context.

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 question the tool answers, then supporting constraints in short sentences; no filler. The parenthetical '(NTA keeps them 40 business days)' and the 'From this service's own record...' clause are slightly dense but each earns its place by bounding result availability.

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?

With an output schema, full parameter coverage and read-only annotations already supplied, the description only needs to add scope and availability constraints, which it does (corporations only, 40-business-day source retention, 30-day free window, cursor paging). Nothing essential for a correct call is missing, though explicit guidance on behavior when 'since' predates the retention window would close the last gap.

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 schema already documents since, limit, cursor and event_type thoroughly, including the enum. The description's 'since a date', 'page with next_cursor' and the colloquial event vocabulary ('newly registered', 'published details changed', 'cancelled or expired') loosely map to code values but add little beyond the schema's own enum descriptions. Baseline 3 applies.

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 and verb set: corporations newly registered as qualified invoice issuers, with details changed, cancelled or expired, sourced from NTA daily difference files. The 'Corporations only' clause sharply bounds the scope. It does not explicitly name the sibling invoice_registration_lookup as the alternative for single-record lookups, so sibling differentiation is left implicit.

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?

'since a date' and 'page with next_cursor' imply the incremental-sync use case, and the free/retention windows hint at when the tool is viable. But there is no explicit when-to-use versus when-not, and no pointer to invoice_registration_lookup or catalog for other needs — the agent must infer the routing.

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