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

Annotations already mark this as non-read-only, destructive and open-world, so the safety profile is covered. The description adds genuinely useful side-effect detail the annotations cannot convey: no stock movement, no invoicing, no payment, nothing received, and it names the underlying endpoint. It stops short of stating auth requirements or what happens on duplicate submissions (idempotentHint=false).

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 plus the endpoint, front-loaded with the WRITE marker and the resulting state. Every sentence carries information, though the raw POST path is the least valuable element for an agent choosing a tool.

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?

With no output schema, the description must carry the behavior, and it does: it defines the resulting document state and explicitly enumerates what does not happen. Combined with 83% schema coverage on six parameters, an agent has enough to invoke it correctly, though error/validation behavior is unaddressed.

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 83%, so the schema already documents supplier_id, type_id, location_id, unit_price and the row SKU guidance. The description adds only the supplier relationship and the PENDING status, no new parameter-level meaning such as defaults for location or type. Baseline 3 is appropriate when 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?

States a specific verb and resource ('create a NEW purchase order'), names the required relationship ('to an existing supplier'), and pins the resulting state ('PENDING status'). It is distinguishable at a glance from the sibling megaventory_create_sales_order and from the list_purchase_orders read tools.

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 gives clear context for use by spelling out that verifying and receiving happen in Megaventory rather than through this server, which tells the agent this tool is for draft creation only. It does not name an explicit alternative tool or exclusion set, so it stops short of a 5.

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