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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real context beyond that: newest-first ordering, the company-level approval-circulation prerequisite, and the API-key/access requirement.

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?

Leads with what the tool returns, then ordering, then filtering, then caveats and auth. Every sentence carries information; the auth note is slightly boilerplate but still useful for a first call.

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 full schema coverage and pre-existing safety annotations, this is nearly complete. Without an output schema it would help to say more explicitly what fields each row returns, but the opener covers this adequately.

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 schema already documents all five parameters including the status enum values. The description restates those values and the waiting_for_me meaning, adding only the ordering note and the circulation caveat, so baseline 3 is appropriate.

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?

Specific verb 'Lists' plus resource 'purchase invoices', with scope details (supplier, amount, circulation status) and stated ordering 'newest first'. An agent can distinguish it from procountor_get_purchase_invoice and procountor_list_sales_invoices without opening any 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?

Explicitly explains how to narrow results via status filter or waiting_for_me, and states the precondition that approval circulation must be enabled in the company. It does not name sibling tools to avoid, so it stops short of the top band.

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