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

Annotations declare the mutation and open-world profile, and the description goes well beyond them: no payment occurs, the order remains unpaid until human checkout, no account/API key is needed, and unpaid orders are auto-deleted after 72 hours. These are exactly the non-obvious operational facts an agent needs.

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-loads the crucial caveat ('this does not pay for anything') before detail, which is the right ordering for a high-risk misconception. It is slightly long and repeats the 'you are not the payer' idea twice, but each remaining sentence carries distinct operational content.

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 non-idempotent mutation with nested objects and no output schema, the description covers the human-in-the-loop requirement, the deletion window, and the payUrl return, and names the follow-up status tool. The gap is parameter-level completeness for placedBy/clientReference, which neither schema nor prose fully closes.

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 only 60%, and the description adds essentially no field-level meaning — it never explains items, quantity defaults, placedBy, clientReference, or notes. Its only parameter-adjacent statement implies the contact email matters, which the schema already says far more precisely.

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 ('Open a pending order for a client') plus a second concrete effect ('return a payment link'). The 'IMPORTANT: this does not pay for anything' clause sharply distinguishes it from anything resembling a payment or fulfillment tool among the 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?

Gives real pre-call guidance ('Confirm the placements and the total with a human before calling this') and post-call routing (send the link, and consult check_order_status before declaring anything bought), naming a sibling explicitly. It stops short of saying when NOT to use it (e.g. to reorder or to check status), but the workflow framing is unusually clear.

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