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

Annotations already declare readOnly/openWorld/non-destructive, so the safety profile is covered; the description adds genuinely new behavior: newest-first ordering, inclusion of cancelled documents, the 100-per-page cap with next_cursor chaining, and the auth requirement (Cotlet API key with app access). That is well beyond what the structured fields convey.

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?

It is front-loaded and readable, but the first two sentences are largely redundant — 'newest first' and the invoice/credit-note enumeration appear twice, consuming space without adding information. Tighter phrasing would earn more here.

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 read-only list tool with a fully documented input schema and no output schema, the description supplies the essentials an agent needs: what is returned, ordering, pagination mechanics, filtering options, and the auth prerequisite. Nothing material 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%, so the schema already documents limit/cursor/client_rfc/issued_since/issued_until, making 3 the baseline. The description adds little parameter-level detail beyond restating filters and the cursor round-trip, which the schema text already provides.

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 (Lists) and resource (CFDI documents: invoices, credit notes, cancelled ones) and enumerates the returned fields (folio, client, total, status). It is distinguishable from sibling facturama_get_invoice (single document) and facturama_list_clients without opening a 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 implies usage via 'Filter by issue date or client RFC', telling the agent this is the collection endpoint for broad retrieval, but it never states when to prefer it over facturama_get_invoice for a single document, and offers no explicit when-not guidance.

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