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

Annotations already declare destructiveHint=true, idempotentHint=false, openWorldHint=true and readOnlyHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral fact (no money is collected or transferred), but it never addresses the destructive aspect — e.g. whether an existing payment link is overwritten — which is exactly what the destructiveHint implies.

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?

Two short, front-loaded sentences with essentially no filler; the constraint clause is placed immediately after the action. It is appropriately sized for a 4-parameter mutation.

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 destructive, non-idempotent mutation the description covers the money-movement boundary but omits prerequisites (valid task/offer state, ownership via actorId) and the effect on any previously set link. The absence of an output schema is acceptable since the return is a simple acknowledgement, but the behavioral gaps leave it only minimally complete.

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?

With 50% schema coverage, the description partially compensates: it tells the agent that 'link' is a PayPal Invoice URL and that 'method' distinguishes FPS/OTHER arrangements, which enriches the enum beyond the bare values. However it says nothing about 'id' (already documented) or about whether 'link' is conditionally required when method=PAYPAL, so the coverage gap is only partly closed.

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 names a specific action (supplying a PayPal Invoice URL / recording FPS or OTHER) against a payment artifact, and the 'Does not collect or transfer money' clause scopes it apart from actual money movement. It is clear what the tool does, though it never explicitly contrasts itself with the sibling tools mark_payment_paid / mark_payment_received.

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?

Usage is implied: use this to arrange how payment will be handled (external URL or offline method), not to move funds. The 'Does not collect or transfer money' boundary helps route away from payment-settlement tools, but there is no explicit when-to-use statement or named alternative, leaving the agent to infer the boundary.

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