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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), and the description adds real context: what data comes back, that duplicate warnings are matched by multiple fields, and the auth requirement (Cotlet API key with app access). It does not mention pagination or rate limits, but adds meaningful value over the annotations.

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-loaded with the purpose and return payload, then workflow and auth. There is some density in the long enumeration of duplicate-warning match fields, but no sentence is wasted and structure is logical.

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?

No output schema exists, so the description correctly carries the return-value burden and does so thoroughly, plus it supplies the auth prerequisite. It is nearly complete for a single-parameter read tool, missing only minor details like error/empty behavior for the duplicate warning.

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% and the single parameter is fully documented in the schema as 'Purchase invoice ID from list_purchase_invoices.' The description adds no further parameter meaning, so this sits at the baseline 3 where the schema does the heavy lifting.

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 (get) plus resource (purchase invoice), and it enumerates the returned payload (supplier, amounts, dates, stamps, comments, duplicate warnings). This clearly distinguishes it from procountor_list_purchase_invoices and procountor_get_sales_invoice 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?

States an explicit workflow position: 'Use it before verify_purchase_invoice or approve_purchase_invoice,' which tells the agent when this tool fits. It does not, however, name when NOT to use it or route to list_purchase_invoices as the alternative for browsing.

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