Get Vat Periods

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

Annotations already cover the read-only/idempotent/destructive profile, so the bar is lower. The description adds meaningful context by revealing that the tool is the prerequisite source of period_id and specifying the returned data. Minor omissions like pagination behavior are acceptable given annotation coverage.

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 sentences, front-loaded with the action and resource, followed by usage guidance in the second sentence. Every clause adds value with no redundancy.

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?

For a simple read-only list tool with three optional params and full schema coverage, the description adequately enumerates return fields, explains the central purpose (period_id for other tools), and pairs well with safety annotations. No critical information 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 description coverage is 100%, so the baseline applies. The description's status list omits 'ready' compared to the schema, and it adds no new parameter meaning beyond the schema's own descriptions. No credit beyond baseline.

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?

Purpose is explicit: 'List the company's VAT return periods and their status' with enumeration of statuses and returned fields. It distinguishes itself from the broader VAT tool family by positioning itself as the primary source of period_id, even if it does not name a specific sibling.

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?

Provides explicit when-to-use guidance with trigger phrases ('which quarters are outstanding', 'have I filed Q1') and use cases ('before calculating/locking/submitting'). It also explains why to use it first: it 'gives you the period_id you need for the other VAT tools.'

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