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

With all annotations false, the description carries the burden of explaining behavior. It adds meaningful context: tolerances are percentages allowed before a GRN is flagged, line quantities are whole units, and IDs follow a PO-0001 pattern. It does not cover response shape or auth, but the annotations already flag non-readonly, non-idempotent behavior.

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?

Four short sentences each carry distinct information: purpose, line structure, tolerance semantics, and ID/plan context. There is no filler, repetition of schema defaults, or unnecessary detail.

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?

The description covers the business role, line constraints, tolerance meaning, and ID format, which is strong for a create tool. However, with no output schema it never states what a successful call returns, and the relationship between the user-supplied 'reference' and generated 'PO-0001' IDs is left ambiguous.

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 baseline is 3. The description adds value beyond the schema by explaining that tolerance percentages govern when a GRN is flagged and that ordered quantities are whole units. It does not elaborate on reference or supplier, but the schema already documents those fields.

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 opens with a specific verb and resource, 'Create a purchase order,' and frames the PO as the document goods are received against. It adds concrete details about lines, tolerances, and ID format, making the tool's purpose unmistakable and clearly distinct from the GRN and license siblings.

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 description gives clear context by positioning the PO as the upstream document for GRN flagging, so an agent can infer when to create one. However, it never explicitly names alternatives like grn_add or states when not to use this tool, leaving usage to be inferred from sibling names and workflow framing.

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