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

Annotations already declare the safety profile (non-read-only, non-destructive, non-idempotent, closed-world), so the description's burden is lower. It adds genuinely new behavioral information not present in structured data: a fixed price of $0.20 per call, which matters for a paid, non-idempotent tool. It stops short of describing failure modes or limits on input size.

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?

Three short sentences with the core capability front-loaded and the cost disclosure early. The trailing use-case sentence is slightly fragmentary grammatically but is short and adds contextual value rather than padding.

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 single-string-input tool with no output schema, the enumeration of extracted fields effectively communicates the expected return shape, and the price is disclosed. Only minor gaps remain (input format/size expectations, behavior on unparseable documents).

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?

There is a single parameter with 100% schema description coverage ('Document text to process.'), so the schema already carries the semantics and baseline 3 applies. The description's list of extracted fields adds context about what the tool reads from the document but does not elaborate on the 'document' parameter itself.

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?

The description uses a specific verb ('Extract') and resource ('purchase order') and enumerates the fields it pulls out (buyer, supplier, items, quantities, terms). An agent can tell this apart from fikra_compare_purchase_orders (comparison) and fikra_extract_invoice (different document type), though the description never explicitly names those alternatives.

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?

The phrase 'Getting PO data into procurement or ERP systems' implies a usage context but does not say when to choose this over siblings like fikra_compare_purchase_orders or fikra_generate_procurement_report, nor any prerequisites or exclusions. Usage is inferable rather than stated.

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