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

Annotations already cover read-only and non-destructive behavior, while the description adds the required 'invoice' scope, the endpoint, and the pagination convention for next_offset. It does not cover rate limits or error behavior, but it is substantially more informative than the annotations alone.

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-loads the resource and returned fields, then covers filtering, scope, endpoint, and pagination with no wasted sentences. The structure lets an agent quickly extract both selection and invocation details.

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?

Despite no output schema, the description explains the response shape (count, total, next_offset, items) and how to page using offset. For a read-only list tool with 100% schema coverage and clear annotations, this is complete enough to invoke correctly.

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 parameters like q, sort, with, limit, filter, offset, and contact_id are already well documented in the schema. The description highlights contact_id, filter, and the next_offset-to-offset paging pattern but does not add detail beyond the schema for the remaining parameters.

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 verb and resource ('List invoices') and enumerates the returned fields (number, contact, dates, total, currency, status). This clearly distinguishes it from sibling detail tools such as smallinvoice_get_invoice.

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?

Explains how to narrow results via contact_id or a JSON filter and notes the required 'invoice' scope. It does not explicitly name when to use smallinvoice_get_invoice instead, so the alternative routing is only implied.

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