verifactu_calendar

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered and the description's 'Free' note usefully adds cost/paywall context. It also discloses that results come with sources and indicate what is still pending publication, which tells the agent the data may be incomplete — but it says nothing about refresh cadence or how current the deadlines are, which matters for a time-sensitive legal calendar.

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?

Two short sentences with the resource and its coverage front-loaded, followed by the caveat about pending publication. The one-word 'Free.' fragment is slightly abrupt but carries real value about pricing, so nothing is wasted.

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 no parameters and an output schema present, the description does not need to explain return values, and it is complete enough for an agent to call and correctly interpret the result. The only meaningful omission is the data's currency or last-updated status for a deadline-oriented tool.

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?

There are zero parameters, so baseline is 4; the description appropriately spends no space on arguments. The only semantic risk — whether the calendar can be scoped by date, region, or business type — is not addressed, but with an empty schema there is nothing to clarify.

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 names the specific resource (legal deadlines for VERI*FACTU and mandatory B2B e-invoicing in Spain) and its scope, which is clearly distinct from the sibling tools that all validate, hash, or generate verification artifacts. It is not phrased as a verb, but the resource and its domain are unambiguous, so an agent can tell this is the informational lookup among the validation tools.

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?

Usage is only implied: an agent can infer this is the tool to call when it needs compliance dates rather than validation results. There is no explicit statement of when to use it, no exclusion of cases, and no reference to a sibling alternative or prerequisite, though in practice no sibling covers this information.

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