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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds genuinely new behavioral context: nothing is charged by this call, the person must open checkout_url and pay, and the action should be treated as sensitive. It stops short of describing failure modes (e.g., expired links, tier/product-count mismatch).

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 sentences, zero filler, and the write/sensitivity warning is front-loaded before the mechanics. Every sentence earns its place.

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 carries the return-value burden and does name checkout_url and the follow-up tool. It does not mention what else comes back (order identifier, expiry) or the idempotency behavior the schema hints at, leaving a small gap.

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 100%, so the schema already documents tier, products, url/notes, and idempotency_key semantics. The description adds only the confirmation advice about tier, price, and product links, which is procedural rather than additional parameter meaning. Baseline 3 applies.

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: 'Saves a pending testing order and creates a secure Stripe-hosted checkout link.' The 'testing order' framing cleanly separates it from the sibling create_contribution_checkout without needing to open either 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?

Gives real preconditions ('confirm the tier, price, and product links with the person first') and routes the agent to get_checkout_status for the follow-up payment check. It does not explicitly say when to choose this over create_contribution_checkout, but the testing/contribution distinction is carried by the name.

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